ChatGPT answers, unedited

Yes. For a headless Shopify + custom storefront, I’d focus on affiliate platforms that can track conversions through APIs/webhooks rather than depending entirely on a Shopify App Store checkout integration.

Platforms worth evaluating

The particularly relevant one: Refersion

Refersion has unusually explicit documentation for your architecture. It says headless Shopify stores can be integrated using GraphQL Storefront API, Shopify API/JS Buy SDK, cart attributes, or cross-domain tracking, with additional developer work required. Refersion Help Center Refersion Help Center

More importantly, as of August 2026, Refersion released its v2026-08 API and describes it as the API its own merchant application uses. The API exposes affiliates, conversions, orders, offers and clicks, and supports webhooks for conversion/status events. Refersion

That makes an architecture like this feasible:

Affiliate link
      ↓
Custom storefront
      ↓
Your backend / tracking layer
      ↓
Shopify Storefront API
      ↓
Shopify checkout
      ↓
Order/conversion event
      ↓
Affiliate platform API/webhook
      ↓
Commission + attribution

You don't necessarily need your custom storefront to behave like a conventional Shopify theme.

Refersion also explicitly says that if a platform isn't directly supported, you can use its API to track orders, and it offers custom development for Enterprise customers. Refersion

One important architectural question

I'd distinguish between "has an API" and "can actually handle headless attribution."

For your setup, I'd require the vendor to demonstrate these four things:

• Click attribution: affiliate URL → your custom domain → persistent affiliate identifier.
• Checkout continuity: identifier survives your custom storefront → Shopify checkout.
• Server-side conversion tracking: your backend can send the completed Shopify order to the affiliate platform.
• Webhooks/API reconciliation: refunds, cancellations and commission status can be synchronized without relying on browser pixels.

Shopify itself supports this sort of architecture: its current headless model exposes the Storefront API and Customer Account API for custom storefronts. Shopify

If you tell me roughly your scale (e.g. 50 affiliates vs. 10,000+, monthly orders, and whether you need influencers/creators as well as traditional affiliates), I can narrow these down to 2–3 platforms and compare their API capabilities, attribution model, Shopify headless implementation, payouts, pricing, and developer effort.

More importantly, as of August 2026, Refersion released its v2026-08 API and describes it as the API its own merchant application uses. The API exposes affiliates, conversions, orders, offers and clicks, and supports webhooks for conversion/status events. refersion.com

That makes an architecture like this feasible:

Affiliate link
      ↓
Custom storefront
      ↓
Your backend / tracking layer
      ↓
Shopify Storefront API
      ↓
Shopify checkout
      ↓
Order/conversion event
      ↓
Affiliate platform API/webhook
      ↓
Commission + attribution

You don't necessarily need your custom storefront to behave like a conventional Shopify theme.

Refersion also explicitly says that if a platform isn't directly supported, you can use its API to track orders, and it offers custom development for Enterprise customers.

One important architectural question

Yes. For a headless Shopify + custom storefront, I’d focus on affiliate platforms where the tracking/conversion layer can be integrated independently of the Shopify frontend.

Platforms worth evaluating

Refersion is particularly relevant to your architecture

Refersion now explicitly documents headless Shopify integrations. Their supported approaches include Shopify's GraphQL Storefront API, Shopify JS Buy SDK/API integrations, cart attributes and cross-domain tracking. They note that headless implementations can require developer work because the customer journey may start on your custom domain and finish in Shopify checkout. Refersion Help Center

More importantly, Refersion just released API v2026-08 in August 2026. They describe it as the API their own merchant application uses, with affiliate, conversion, click, order, offer and webhook resources exposed through the API. Refersion

That makes the architecture reasonably clean:

Affiliate link
      ↓
Custom/headless storefront
      ↓
Affiliate tracking ID / cookie / attribution
      ↓
Shopify Storefront API
      ↓
Shopify checkout
      ↓
Order/conversion event
      ↓
Affiliate platform API/webhook
      ↓
Commission + affiliate reporting

Shopify itself supports this kind of architecture: the Storefront API is specifically intended to let you build custom shopping experiences independently of the Shopify-hosted storefront. Shopify Shopify

The key thing I'd validate before choosing

Don't just ask vendors "Do you integrate with Shopify?" That's usually testing the wrong thing. Ask:

1. Can affiliate attribution begin on our non-Shopify domain?
2. Can we capture the affiliate click ID in our custom frontend?
3. Can that ID survive the Storefront API → Shopify checkout transition?
4. Can we send a server-side conversion/order event via API or webhook?
5. Can we reconcile conversions against Shopify order IDs?
6. Can we handle refunds/cancellations and adjust commissions?
7. Can affiliate links, coupons and attribution rules be managed entirely through API?
8. Do they support first-party/server-side tracking rather than requiring Shopify theme JavaScript?

For your specific requirement, Refersion, Everflow, and impact.com are the three I'd put into a technical evaluation, with Refersion getting particular attention because it now explicitly supports headless Shopify and has an API-first architecture. Refersion Help Center Refersion

support.refersion.com
refersion.com
shopify.dev

If you tell me your frontend stack (Next.js/Hydrogen/etc.), whether checkout stays on Shopify, and whether you need influencer + affiliate or just traditional affiliates, I can narrow this to the best 2–3 architectures and show exactly how the tracking flow would work.

That makes the architecture reasonably clean:

Affiliate link
      ↓
Custom/headless storefront
      ↓
Affiliate tracking ID / cookie / attribution
      ↓
Shopify Storefront API
      ↓
Shopify checkout
      ↓
Order/conversion event
      ↓
Affiliate platform API/webhook
      ↓
Commission + affiliate reporting

Shopify itself supports this kind of architecture: the Storefront API is specifically intended to let you build custom shopping experiences independently of the Shopify-hosted storefront.

The key thing I'd validate before choosing

Don't just ask vendors "Do you integrate with Shopify?" That's usually testing the wrong thing. Ask:

Yes. For a headless Shopify + custom storefront, I’d shortlist:

• Refersion — strongest Shopify-specific fit. It explicitly supports headless Shopify, including Storefront API, JS Buy SDK, API-based integrations, and cross-domain tracking. Its new 2026 API is also designed to be API-first. support.refersion.com Refersion
• Everflow — strong choice if you need a more enterprise-grade, highly programmable affiliate/partner platform. It exposes APIs for affiliates, offers, reporting, postbacks, etc. Everflow API
• GoAffPro — Shopify-oriented and has documented support for Shopify's Headless channel/Storefront API, though it's less API-centric than the two above. GoAffPro Documentation

My recommendation: start with Refersion if Shopify is your core commerce backend; choose Everflow if you expect complex partner networks, custom attribution, or multiple commerce systems.

Shopify itself supports the architecture through its Storefront API and Headless channel. Shopify Shopify

If you tell me your affiliate requirements (creator affiliates vs. traditional affiliates, attribution model, payouts, expected scale), I can narrow this to 2–3 platforms.

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate platforms that expose tracking, conversions, commissions, partners, and reporting through APIs/webhooks rather than relying on a Shopify app.

Best fits

My first two to evaluate would be Everflow and impact.com.

1. Everflow — strongest technical fit

Everflow is particularly attractive if your engineering team wants the affiliate system to be another service in your architecture rather than a Shopify app.

Its APIs cover affiliates, offers, advertisers, reporting, marketplace relationships, and more; it also provides webhooks and a JavaScript SDK for client-side click/conversion/impression tracking. Everflow API Everflow API

That makes a flow like this feasible:

Custom Storefront
       │
       ├── Affiliate click/tracking
       │
       ▼
   Everflow
       │
       │ conversion
       ▼
Shopify Checkout
       │
       ▼
Order / conversion event
       │
       ▼
Your backend → Everflow API

This is the option I'd investigate first if API control and architectural flexibility are the priorities.

developers.everflow.io

2. impact.com — strongest broader partnership platform

Impact is compelling if "affiliate" eventually expands into creators, influencers, ambassadors, referral partners, and other partnership types.

It has a REST API for integration and supports tracking, link generation, conversions, commissions, and related workflows. Shopify

Important caveat for your architecture: Impact's current Shopify integration documentation explicitly says its Shopify app requires the storefront landing page to be hosted on Shopify and that custom shopping experiences aren't currently supported. Impact Integrations

So I would not base your headless implementation around the Shopify app. Instead, you'd want to validate the API/direct-tracking architecture with Impact during technical evaluation.

integrations.impact.com

3. PartnerStack — excellent API, different emphasis

PartnerStack has a REST API exposing customers, transactions, deals, leads, partnerships, imports, actions, and webhooks. PartnerStack PartnerStack

I'd put it higher on the list if you're building a partner/referral ecosystem rather than a traditional high-volume ecommerce affiliate network.

docs.partnerstack.com

One architectural point that's important

Shopify itself is actually well suited to this architecture. Its Storefront API is specifically designed for custom storefronts, and Shopify's Headless channel supports multiple storefronts and API credentials. Shopify Shopify

So I wouldn't choose an affiliate provider simply because it has a "Shopify integration." For your setup, I'd evaluate whether it can:

• Generate/deep-link affiliate URLs without Shopify Liquid.
• Track clicks on your custom frontend.
• Persist affiliate attribution through your custom cart/session.
• Receive server-side Shopify order/conversion events.
• Create/update conversions through an API.
• Handle refunds/cancellations and commission reversals.
• Support coupons/coupon attribution.
• Provide webhooks for affiliate/commission events.
• Work without exposing secret API credentials in the browser.
• Handle your custom checkout flow.
• Support multiple storefronts/domains if you'll have them.
• Let you reconcile affiliate conversions against Shopify order IDs.

The server-side conversion/reconciliation piece is particularly important. You don't want the affiliate platform's browser pixel to be your only source of truth.

My shortlist

If I were running the technical RFP, I'd start with:

1. Everflow — best candidate for a deeply customized headless architecture.
2. impact.com — best if creator/influencer/partnership capabilities matter alongside affiliates.
3. PartnerStack — best if this is really a partner/referral ecosystem.
4. Awin — worth evaluating if access to a large established publisher network is important.
5. Shopify Collabs — only if simplicity and Shopify-native operation outweigh API/headless flexibility.

Shopify itself describes custom storefronts as an API-first architecture where you can bring your own frontend and integrate other systems with Shopify's backend, so your instinct to select an affiliate platform based on its APIs rather than its Shopify app is the right one. Shopify

If you tell me rough monthly order volume, affiliate count, and whether you need creators/influencers as well as traditional affiliates, I can narrow this to the best 2–3 platforms and compare their APIs, tracking model, Shopify integration architecture, pricing, and implementation effort.

That makes a flow like this feasible:

Custom Storefront
       │
       ├── Affiliate click/tracking
       │
       ▼
   Everflow
       │
       │ conversion
       ▼
Shopify Checkout
       │
       ▼
Order / conversion event
       │
       ▼
Your backend → Everflow API

This is the option I'd investigate first if API control and architectural flexibility are the priorities.

developers.everflow.io

2. impact.com — strongest broader partnership platform

Impact is compelling if "affiliate" eventually expands into creators, influencers, ambassadors, referral partners, and other partnership types.

It has a REST API for integration and supports tracking, link generation, conversions, commissions, and related workflows. Shopify

Important caveat for your architecture: Impact's current Shopify integration documentation explicitly says its Shopify app requires the storefront landing page to be hosted on Shopify and that custom shopping experiences aren't currently supported. Impact Integrations

So I would not base your headless implementation around the Shopify app. Instead, you'd want to validate the API/direct-tracking architecture with Impact during technical evaluation.

integrations.impact.com

3. PartnerStack — excellent API, different emphasis

PartnerStack has a REST API exposing customers, transactions, deals, leads, partnerships, imports, actions, and webhooks. docs.partnerstack.com docs.partnerstack.com

I'd put it higher on the list if you're building a partner/referral ecosystem rather than a traditional high-volume ecommerce affiliate network.

docs.partnerstack.com

One architectural point that's important

Shopify itself is actually well suited to this architecture. Its Storefront API is specifically designed for custom storefronts, and Shopify's Headless channel supports multiple storefronts and API credentials.

So I wouldn't choose an affiliate provider simply because it has a "Shopify integration." For your setup, I'd evaluate whether it can:

Yes. For a headless Shopify + custom storefront, I’d prioritize platforms where affiliate tracking/conversion reporting can be implemented through APIs or server-side events—not platforms that assume the Shopify theme is rendering the storefront.

Best fits

1. Refersion — probably the cleanest match

Refersion explicitly documents headless Shopify integrations, including Shopify Storefront API/GraphQL, Shopify API-based integrations, cart attributes, and cross-domain tracking. Their documentation says headless implementations may require developer work, but they support the architecture. Refersion Help Center

More importantly, Refersion just released API v2026-08, describing it as the same API their own merchant application uses. Refersion Their platform also explicitly supports using the API to track orders when there isn't a native ecommerce integration. Refersion

I'd shortlist this first if your requirements are:

• Custom React/Next.js/etc. storefront
• Shopify as commerce backend
• Affiliate links/codes
• Your own checkout/customer experience
• Programmatic order/conversion reporting
• Minimal dependence on Shopify theme/app embeds

2. Impact — best for a more sophisticated setup

impact.com has REST APIs for things such as conversion tracking, link generation, and performance data. Shopify also specifically lists Impact API as an affiliate API solution. Shopify

But there's an important caveat: Impact's current Shopify app documentation says its Shopify integration expects the storefront landing page to be hosted on Shopify and that custom shopping experiences aren't currently supported. Impact Integrations

So I would not choose the standard Shopify app integration for your architecture. Instead, I'd evaluate Impact based on its API/server-side integration capabilities.

That's potentially the better option if you need:

• Affiliates + influencers/creators
• Complex commission structures
• Enterprise reporting
• Partner discovery/recruitment
• Multiple partnership types beyond traditional affiliates

3. Awin — strong network, less compelling purely as an API-first choice

Awin has APIs and supports server-to-server tracking. Its Shopify integration also supports S2S tracking. Awin Help Center

However, Awin explicitly says its Shopify app has only been validated with standard Shopify themes, which makes the app itself a poor foundation for a headless implementation. Awin Help Center

I'd consider Awin if access to its publisher network is a major requirement, rather than because it's the cleanest technical fit.

My recommendation

For your particular architecture, I'd rank them:

1. Refersion → 2. Impact → 3. Awin

The key architectural question I'd ask each vendor is:

"Can we run affiliate click attribution and conversion tracking entirely through our custom storefront and Shopify backend APIs, without installing a Shopify theme app or relying on Shopify's rendered storefront?"

That's much more important than simply asking whether they "support Shopify."

For a headless implementation, I'd also specifically require support for:

• Affiliate click → persistent attribution ID
• First-party/server-side tracking
• Shopify order ID passed to the affiliate platform
• GraphQL Storefront API compatibility
• Webhooks or API-based conversion reporting
• Refund/cancellation reversal
• Coupon-code attribution
• Multi-touch or attribution-window configuration
• Consent/privacy controls
• Deduplication with other marketing channels
• Server-side tracking that survives checkout/domain transitions

Refersion looks particularly interesting right now because its newly released API is explicitly API-first rather than merely exposing a limited integration layer. Refersion

If you tell me whether this is DTC/B2C or B2B, and what your storefront stack is (e.g. Next.js + Shopify Storefront API + Shopify checkout), I can narrow this to 2–3 platforms and compare their actual API architecture, tracking flow, webhooks, pricing, and headless implementation effort.

1. Refersion → 2. Impact → 3. Awin

The key architectural question I'd ask each vendor is:

"Can we run affiliate click attribution and conversion tracking entirely through our custom storefront and Shopify backend APIs, without installing a Shopify theme app or relying on Shopify's rendered storefront?"

That's much more important than simply asking whether they "support Shopify."

For a headless implementation, I'd also specifically require support for:

• Affiliate click → persistent attribution ID
• First-party/server-side tracking
• Shopify order ID passed to the affiliate platform
• GraphQL Storefront API compatibility
• Webhooks or API-based conversion reporting
• Refund/cancellation reversal
• Coupon-code attribution
• Multi-touch or attribution-window configuration
• Consent/privacy controls
• Deduplication with other marketing channels
• Server-side tracking that survives checkout/domain transitions

Refersion looks particularly interesting right now because its newly released API is explicitly API-first rather than merely exposing a limited integration layer.

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate platforms that can track conversions through APIs/server-side events rather than relying on a Shopify theme/app pixel.

Best fits

My recommendation: Refersion or Everflow

Refersion is probably the easiest fit if you're fundamentally running a Shopify ecommerce affiliate program. Refersion explicitly documents headless Shopify integrations, including Shopify's GraphQL Storefront API, JS Buy SDK/API-based implementations, cart attributes, and cross-domain tracking. It also exposes an API for custom order tracking. Refersion Help Center Refersion

support.refersion.com

Everflow is the stronger choice if your storefront is highly customized and you want the affiliate platform to behave more like an independent tracking/partner infrastructure layer. Its API is extensive and supports affiliate-side management, reporting, postbacks, etc. Everflow API

developers.everflow.io

I would not make impact.com my first choice for your architecture. Its current Shopify documentation specifically says the Shopify integration requires the storefront landing page to be hosted on Shopify and that custom shopping experiences aren't supported. That's a significant mismatch with a genuinely headless/custom storefront. Impact Integrations

How I'd architect it

With your setup, I'd aim for:

Affiliate link → custom storefront → affiliate click ID persisted → Shopify cart/checkout → server-side conversion event → affiliate platform

Rather than:

Affiliate link → Shopify theme/app → browser pixel → conversion

That's important because Shopify's Storefront API is designed specifically for custom storefronts and Shopify now supports multiple headless storefronts through its Headless channel. Shopify Shopify

For a custom React/Next.js/Hydrogen-style storefront, I'd specifically evaluate each vendor on:

• Server-side conversion API
• Click/session ID generation and persistence
• Cross-domain tracking into Shopify checkout
• Shopify order ID / transaction ID reconciliation
• Coupon-code attribution
• Webhooks
• Subscriptions/reorders
• Refund and cancellation handling
• Multi-store or multi-brand support
• Affiliate payout APIs
• Fraud/duplicate-conversion protection
• Ability to attribute orders without relying on Shopify Liquid/theme scripts

If you tell me your stack (e.g. Hydrogen, Next.js, Remix, custom React) and whether you need affiliates, influencers, or both, I can narrow this to 2–3 platforms and compare their APIs, implementation effort, pricing model, and Shopify headless compatibility.

My recommendation: Refersion or Everflow

Refersion is probably the easiest fit if you're fundamentally running a Shopify ecommerce affiliate program. Refersion explicitly documents headless Shopify integrations, including Shopify's GraphQL Storefront API, JS Buy SDK/API-based implementations, cart attributes, and cross-domain tracking. It also exposes an API for custom order tracking. Refersion Help Center Refersion

support.refersion.com

Everflow is the stronger choice if your storefront is highly customized and you want the affiliate platform to behave more like an independent tracking/partner infrastructure layer. Its API is extensive and supports affiliate-side management, reporting, postbacks, etc. Everflow API

developers.everflow.io

I would not make impact.com my first choice for your architecture. Its current Shopify documentation specifically says the Shopify integration requires the storefront landing page to be hosted on Shopify and that custom shopping experiences aren't supported. That's a significant mismatch with a genuinely headless/custom storefront. integrations.impact.com

How I'd architect it

With your setup, I'd aim for:

Affiliate link → custom storefront → affiliate click ID persisted → Shopify cart/checkout → server-side conversion event → affiliate platform

Rather than:

Affiliate link → Shopify theme/app → browser pixel → conversion

That's important because Shopify's Storefront API is designed specifically for custom storefronts and Shopify now supports multiple headless storefronts through its Headless channel.

For a custom React/Next.js/Hydrogen-style storefront, I'd specifically evaluate each vendor on:

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate platforms that expose tracking, conversions, affiliates, commissions, and webhooks through APIs rather than relying on a Shopify app/UI.

Best fits

Refersion is particularly interesting for your setup. Their documentation now explicitly covers headless Shopify, including GraphQL Storefront API, Shopify API/JS Buy SDK implementations, cart-attribute tracking, and cross-domain tracking. Refersion Help Center Refersion Help Center

More importantly, Refersion just released its v2026-08 API, which is the API their own merchant application uses. It exposes affiliates, conversions, clicks, orders, offers, prospects, promotion methods, and webhooks, with OAuth authentication. That makes it much more compelling for a custom storefront than a platform where the API is basically an afterthought. Refersion

refersion.dev

Partnerize

If you're building something more enterprise/composable, I'd put Partnerize near the top of the shortlist. Their API documentation explicitly says the platform is built API-first, with the web application built on top of the API. The API follows REST conventions and has broad programmatic access. Partnerize API Documentation

That makes it attractive if your architecture looks something like:

Custom storefront → your backend → Shopify Storefront/Admin APIs → affiliate platform

rather than:

Shopify theme → affiliate app → checkout

api-docs.partnerize.com

Everflow

I'd consider Everflow if your requirements are more technically sophisticated—for example, multiple affiliate sources, sub-affiliate structures, detailed attribution, postbacks, custom conversion events, or eventually operating your own partner ecosystem.

Everflow exposes APIs for affiliates and other parts of the platform; its Affiliate API supports offer management, reporting and postbacks, for example. Everflow API

developers.everflow.io

Shopify Collabs

Collabs can work with a custom storefront, but I'd consider it Shopify-centric rather than API-first. Shopify's current documentation says custom storefronts need to handle page-view events, redirects, and the /discount route for personalized affiliate links. Shopify Help Center

That's fine if you want Shopify to remain the center of the affiliate system. It's less attractive if your custom application needs to own the affiliate experience and orchestration.

What I'd shortlist

For your specific architecture, I'd evaluate them in this order:

1. Refersion — easiest combination of Shopify compatibility + headless support + increasingly comprehensive API.
2. Partnerize — strongest candidate if you're operating at enterprise scale and want a genuinely API-first partner platform.
3. Everflow — strongest if technical tracking flexibility and performance-marketing capabilities matter more than Shopify-native simplicity.
4. Shopify Collabs — best if you want the least infrastructure and are comfortable keeping affiliate functionality tightly coupled to Shopify.

Shopify itself supports fully custom storefronts through its Storefront API, so there is no architectural reason your affiliate system has to live in the Shopify frontend. Shopify Shopify

One important architectural question: I'd specifically test how each vendor handles affiliate click → custom-domain session → Shopify cart → Shopify checkout → conversion webhook, because that's where headless implementations can differ substantially. Refersion, for example, explicitly documents several approaches for this flow. Refersion Help Center

If you tell me your affiliate model (standard affiliates vs creators/influencers vs B2B partners), expected order volume, and whether checkout remains Shopify-hosted, I can narrow this to the best 2–3 and compare their APIs, tracking architecture, webhooks, commissions, payouts, and estimated cost.

Partnerize

If you're building something more enterprise/composable, I'd put Partnerize near the top of the shortlist. Their API documentation explicitly says the platform is built API-first, with the web application built on top of the API. The API follows REST conventions and has broad programmatic access. Partnerize API Documentation

That makes it attractive if your architecture looks something like:

Custom storefront → your backend → Shopify Storefront/Admin APIs → affiliate platform

rather than:

Shopify theme → affiliate app → checkout

api-docs.partnerize.com

Everflow

I'd consider Everflow if your requirements are more technically sophisticated—for example, multiple affiliate sources, sub-affiliate structures, detailed attribution, postbacks, custom conversion events, or eventually operating your own partner ecosystem.

Everflow exposes APIs for affiliates and other parts of the platform; its Affiliate API supports offer management, reporting and postbacks, for example. developers.everflow.io

developers.everflow.io

Shopify Collabs

Collabs can work with a custom storefront, but I'd consider it Shopify-centric rather than API-first. Shopify's current documentation says custom storefronts need to handle page-view events, redirects, and the /discount route for personalized affiliate links.

That's fine if you want Shopify to remain the center of the affiliate system. It's less attractive if your custom application needs to own the affiliate experience and orchestration.

What I'd shortlist

For your specific architecture, I'd evaluate them in this order:

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate platforms that expose conversion tracking, affiliate management, and reporting through APIs rather than requiring their Shopify app/UI to sit in the storefront.

Best fits

My first two would be Refersion and Everflow.

1. Refersion — probably the easiest Shopify-headless fit

Refersion now explicitly documents headless Shopify integrations, including GraphQL Storefront API, Shopify API/JS Buy SDK implementations, cart-attribute tracking, and cross-domain tracking. Their documentation specifically says headless implementations require additional development rather than simply installing their Shopify app. Refersion Help Center Refersion Help Center

More importantly, Refersion just released API v2026-08, designed as an API-first surface: affiliates, conversions, orders, clicks, offers, prospects, promotion methods and webhooks are exposed through the API. Refersion

That makes it particularly attractive if your architecture looks like:

Custom storefront → Shopify Storefront API → Shopify checkout → Refersion API/webhooks

You can keep the affiliate logic largely independent of the storefront.

refersion.com

2. Everflow — better if attribution is sophisticated

I'd look at Everflow if you expect more complex requirements: multiple traffic sources, sophisticated attribution, server-to-server tracking, media buying, sub-affiliates, or a broader performance-marketing setup.

It's less "Shopify affiliate app" and more "build affiliate/performance infrastructure around your commerce stack," which can actually be an advantage for a heavily customized storefront.

everflow.io

3. PartnerStack

PartnerStack has a proper REST API for both partners and vendors, with resource-oriented endpoints and programmatic access to partner-program objects. PartnerStack PartnerStack

I'd choose it primarily if "affiliate" is really part of a broader partner/referral ecosystem—especially SaaS, resellers, referrals, or B2B partnerships. For a conventional DTC Shopify affiliate program, Refersion/Everflow are more natural fits.

partnerstack.com

One important architectural point

Don't make the affiliate platform depend on the Shopify theme/app layer.

Shopify explicitly supports a bring-your-own-stack architecture through its Storefront API, so your custom storefront can remain completely independent of Shopify's standard frontend. Shopify Shopify

I'd therefore evaluate each platform against these requirements:

• Server-to-server conversion API — ideally send the Shopify order/conversion directly from your backend.
• Click/referral ID persistence — capture the affiliate identifier on your custom frontend and carry it through cart/checkout.
• Shopify order-ID reconciliation — conversion should ultimately map to the Shopify order.
• Webhooks — affiliate/conversion status changes should flow back into your systems.
• Coupon attribution — useful as a fallback when referral cookies/IDs aren't available.
• First-party tracking — increasingly important for privacy/browser restrictions.
• GraphQL/REST APIs with stable versioning — don't choose a platform where the API is an afterthought.
• No requirement to render their JS widget/storefront components — particularly important for your custom frontend.

Refersion is unusually compelling here because its current API is explicitly the same API its own merchant application uses, rather than a reduced API bolted onto the product afterward. Refersion

If you tell me your approximate order volume, whether you're DTC or B2B, and whether you need an affiliate marketplace/network or just software to run your own affiliate program, I can narrow this to 2–3 platforms and compare their APIs, tracking architecture, Shopify compatibility, and pricing.

Refersion now explicitly documents headless Shopify integrations, including GraphQL Storefront API, Shopify API/JS Buy SDK implementations, cart-attribute tracking, and cross-domain tracking. Their documentation specifically says headless implementations require additional development rather than simply installing their Shopify app. Refersion Help Center Refersion Help Center

More importantly, Refersion just released API v2026-08, designed as an API-first surface: affiliates, conversions, orders, clicks, offers, prospects, promotion methods and webhooks are exposed through the API. Refersion

That makes it particularly attractive if your architecture looks like:

Custom storefront → Shopify Storefront API → Shopify checkout → Refersion API/webhooks

You can keep the affiliate logic largely independent of the storefront.

refersion.com

2. Everflow — better if attribution is sophisticated

I'd look at Everflow if you expect more complex requirements: multiple traffic sources, sophisticated attribution, server-to-server tracking, media buying, sub-affiliates, or a broader performance-marketing setup.

It's less "Shopify affiliate app" and more "build affiliate/performance infrastructure around your commerce stack," which can actually be an advantage for a heavily customized storefront.

everflow.io

3. PartnerStack

PartnerStack has a proper REST API for both partners and vendors, with resource-oriented endpoints and programmatic access to partner-program objects. docs.partnerstack.com docs.partnerstack.com

I'd choose it primarily if "affiliate" is really part of a broader partner/referral ecosystem—especially SaaS, resellers, referrals, or B2B partnerships. For a conventional DTC Shopify affiliate program, Refersion/Everflow are more natural fits.

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate platforms that expose tracking, conversions, affiliates, commissions, and webhooks through APIs rather than relying on a Shopify theme/app.

Best fits

1. Refersion — probably my first choice

refersion.com

Refersion is particularly interesting right now because it released its v2026-08 API in August 2026. The company says the API is the same API its own merchant application uses, rather than a reduced API layered on top of the product. It exposes affiliate and conversion management plus webhooks. Refersion

More importantly for your architecture, Refersion has specific documentation for headless Shopify, including Shopify Storefront API, JS Buy SDK/API-based integrations, cart attributes, and cross-domain tracking. Refersion Help Center

So your architecture could look roughly like:

Custom storefront → Shopify Storefront API → Shopify checkout

Custom storefront → Refersion tracking/API → affiliate attribution

I'd put this at #1 if affiliate/ecommerce functionality is the primary requirement.

2. UpPromote — very practical for headless Shopify

uppromote.com

UpPromote explicitly documents support for Hydrogen and custom headless stores. Its third-party tracking can be installed directly into your custom storefront, with either redirect/linker tracking or cart tracking. It also supports Shopify Storefront API-based cart tracking. UpPromote Docs

It additionally exposes an API and webhooks for affiliates, referrals, affiliate status changes, and payments. UpPromote Docs

I'd choose this if you want something more Shopify-oriented and potentially simpler to implement than an enterprise affiliate platform.

3. PartnerStack — excellent API, different use case

partnerstack.com

PartnerStack has a well-developed REST API covering the core objects of partner programs. PartnerStack PartnerStack

I'd consider it if your "affiliate" program is really becoming a partner/referral/reseller ecosystem—for example, agencies, creators, technology partners, or B2B referral partners.

For a conventional DTC Shopify affiliate program, though, I'd generally favor Refersion or UpPromote.

One I'd be cautious about: impact.com

impact.com

impact.com is extremely capable, but its current Shopify documentation specifically says its Shopify integration requires the store's landing page to be hosted on Shopify and that custom shopping experiences aren't currently supported. Impact Integrations

That makes it less attractive for the architecture you're describing unless you're prepared to implement a more bespoke integration outside its standard Shopify connector.

My shortlist

If I were evaluating this for your stack, I'd run an implementation POC with:

1. Refersion — best overall match for headless Shopify + custom affiliate tracking.
2. UpPromote — best Shopify-native/headless-friendly alternative.
3. PartnerStack — best if the program is evolving toward broader partnerships rather than just affiliates.
4. impact.com — consider for enterprise-scale partnership/affiliate operations, but don't assume its Shopify connector works with your custom storefront.

One important architectural point: don't evaluate these based solely on whether they have a Shopify app. Your key question is whether they can attribute an affiliate click on your custom domain all the way through a Shopify checkout/order, preferably with server-side conversion tracking/webhooks so you're not dependent on browser cookies or theme scripts.

Shopify itself supports custom storefronts through the Storefront API, so there's no architectural requirement that your affiliate platform be embedded in a Shopify theme. Shopify Shopify

If you tell me your frontend stack (Next.js/Hydrogen/etc.), checkout flow, and whether this is DTC or B2B, I can narrow this to the 2–3 best options and compare API coverage, tracking model, webhooks, Shopify checkout compatibility, and likely implementation effort.

More importantly for your architecture, Refersion has specific documentation for headless Shopify, including Shopify Storefront API, JS Buy SDK/API-based integrations, cart attributes, and cross-domain tracking. Refersion Help Center

So your architecture could look roughly like:

Custom storefront → Shopify Storefront API → Shopify checkout

Custom storefront → Refersion tracking/API → affiliate attribution

I'd put this at #1 if affiliate/ecommerce functionality is the primary requirement.

2. UpPromote — very practical for headless Shopify

uppromote.com

UpPromote explicitly documents support for Hydrogen and custom headless stores. Its third-party tracking can be installed directly into your custom storefront, with either redirect/linker tracking or cart tracking. It also supports Shopify Storefront API-based cart tracking. UpPromote Docs

It additionally exposes an API and webhooks for affiliates, referrals, affiliate status changes, and payments. UpPromote Docs

I'd choose this if you want something more Shopify-oriented and potentially simpler to implement than an enterprise affiliate platform.

3. PartnerStack — excellent API, different use case

partnerstack.com

PartnerStack has a well-developed REST API covering the core objects of partner programs. PartnerStack PartnerStack

I'd consider it if your "affiliate" program is really becoming a partner/referral/reseller ecosystem—for example, agencies, creators, technology partners, or B2B referral partners.

For a conventional DTC Shopify affiliate program, though, I'd generally favor Refersion or UpPromote.

One I'd be cautious about: impact.com

impact.com

impact.com is extremely capable, but its current Shopify documentation specifically says its Shopify integration requires the store's landing page to be hosted on Shopify and that custom shopping experiences aren't currently supported.

That makes it less attractive for the architecture you're describing unless you're prepared to implement a more bespoke integration outside its standard Shopify connector.

My shortlist

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate platforms with a real API/server-side tracking layer rather than platforms whose Shopify integration assumes a standard Liquid storefront.

Best fits

1. Everflow — my first choice

developers.everflow.io

Everflow is particularly attractive if your architecture is Shopify backend → custom frontend → your own middleware/backend. Its API covers advertisers, offers, affiliates, reporting, and other core objects, while its platform also provides webhooks and a JavaScript SDK for click/conversion/impression tracking. Everflow API Everflow API

That means you aren't forced to make the Shopify app/plugin the center of your affiliate implementation.

I'd shortlist Everflow if you need:

• Affiliate links and attribution on a non-Shopify frontend
• Server-to-server conversion tracking
• Custom commission logic
• Webhooks
• Your own attribution/middleware layer
• Multiple storefronts or channels eventually

2. PartnerStack — strong API-first option

docs.partnerstack.com

PartnerStack has REST APIs for both vendors and partners, giving you direct programmatic access to core partner-program objects. PartnerStack PartnerStack

I'd lean toward it if your "affiliate" program is really becoming a partner/referral ecosystem—for example, agencies, creators, technology partners, or B2B partners—rather than simply a traditional coupon/affiliate network.

3. Refersion — worth evaluating for Shopify

Refersion explicitly documents headless Shopify integrations, including integrations using the Shopify GraphQL Storefront API, Shopify API/JS Buy SDK, cart attributes, and cross-domain tracking. Refersion Help Center

The catch is important: Refersion says headless implementations are custom and may require developer resources. So it can work, but I'd put Everflow ahead of it if your primary requirement is architectural flexibility.

One I'd be cautious about: impact.com

impact.com

impact.com is a very capable partnership platform, but its documented Shopify integration currently says the Shopify store must have its landing page hosted on Shopify and that custom shopping experiences aren't supported by that integration. Impact Integrations

So although impact.com's broader APIs are powerful, I wouldn't select it based on its Shopify app if your custom storefront is a hard requirement. You'd want impact.com to explicitly validate your proposed API/server-side architecture before committing.

Important architectural point

Your Shopify setup itself is well suited to this approach. Shopify's Storefront API is specifically designed for custom storefronts, and Shopify's Headless channel supports multiple custom storefronts and order attribution. Shopify Shopify

I'd architect the affiliate layer roughly like:

Affiliate click
      ↓
Affiliate platform
      ↓
Custom storefront
      ↓
Your tracking/session layer
      ↓
Shopify Storefront API
      ↓
Shopify checkout
      ↓
Order/conversion event
      ↓
Affiliate platform API / S2S conversion

My shortlist would therefore be:

1. Everflow — best overall for a technically sophisticated headless build.
2. PartnerStack — best if you're building a broader partner/referral ecosystem.
3. Refersion — good if you want something more Shopify-centric but can accommodate custom integration work.
4. impact.com — consider for enterprise partnership breadth, but validate the headless architecture first.

If you tell me whether this is DTC affiliate marketing (creators/coupons/content) or B2B partners/referrals, I can narrow this to the 2–3 platforms I'd actually RFP, including API capabilities, Shopify/headless implementation approach, pricing model, and attribution options.

3. Refersion — worth evaluating for Shopify

Refersion explicitly documents headless Shopify integrations, including integrations using the Shopify GraphQL Storefront API, Shopify API/JS Buy SDK, cart attributes, and cross-domain tracking. Refersion Help Center

The catch is important: Refersion says headless implementations are custom and may require developer resources. So it can work, but I'd put Everflow ahead of it if your primary requirement is architectural flexibility.

One I'd be cautious about: impact.com

impact.com

impact.com is a very capable partnership platform, but its documented Shopify integration currently says the Shopify store must have its landing page hosted on Shopify and that custom shopping experiences aren't supported by that integration. integrations.impact.com

So although impact.com's broader APIs are powerful, I wouldn't select it based on its Shopify app if your custom storefront is a hard requirement. You'd want impact.com to explicitly validate your proposed API/server-side architecture before committing.

Important architectural point

Your Shopify setup itself is well suited to this approach. Shopify's Storefront API is specifically designed for custom storefronts, and Shopify's Headless channel supports multiple custom storefronts and order attribution. shopify.dev shopify.dev

I'd architect the affiliate layer roughly like:

Affiliate click
      ↓
Affiliate platform
      ↓
Custom storefront
      ↓
Your tracking/session layer
      ↓
Shopify Storefront API
      ↓
Shopify checkout
      ↓
Order/conversion event
      ↓
Affiliate platform API / S2S conversion

My shortlist would therefore be:

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate platforms that let you control tracking and conversion attribution through APIs/webhooks rather than relying on a Shopify theme/app script.

Best fits

1. Refersion — my first choice for your architecture

Refersion is particularly interesting because it explicitly supports headless Shopify. Its documentation describes integrations using the Shopify GraphQL Storefront API, Shopify APIs/JS Buy SDK, cart attributes, and cross-domain tracking. Refersion Help Center Refersion Help Center

More importantly, Refersion just introduced a new API-first architecture. Its August 2026 API is the same API its own merchant application uses, with affiliate management, conversion management, order-based crediting, and webhooks exposed through the API. Refersion

That makes it a particularly good match if your architecture looks like:

Custom storefront
      │
      ├── affiliate/referral URL
      │
      ▼
Your frontend / backend
      │
      ├── Shopify Storefront API
      │
      └── Refersion API
              │
              ├── affiliates
              ├── conversions
              └── webhooks

Refersion also supports server-side order tracking, which is preferable for a headless implementation because you don't want affiliate attribution to depend entirely on client-side JavaScript. Refersion

refersion.dev

2. impact.com — best if you need enterprise partnership capabilities

I'd put impact.com on the shortlist if you're going beyond a straightforward affiliate program—for example, affiliates + influencers + strategic partners + media partners, sophisticated attribution, multiple commission structures, etc.

Its API-oriented model is well suited to a custom commerce stack, although I'd evaluate the implementation effort and pricing against Refersion before committing.

impact.com

3. PartnerStack — excellent API, but depends on your business model

PartnerStack has a genuine REST Partner API and Vendor API, giving developers programmatic control over partners, rewards, customers, and related objects. PartnerStack PartnerStack

I'd favor it if your "affiliate" program is really closer to a partner/referral ecosystem, particularly B2B/SaaS. For a consumer Shopify store where the main requirement is "affiliate sends customer → customer buys product → commission gets attributed," I'd investigate Refersion and impact.com first.

docs.partnerstack.com

4. Shopify Collabs — easiest, but less API-first

Collabs can work with custom storefronts, but Shopify's own documentation says custom storefronts need to send Shopify page-view events and handle redirects/discount routes for personalized affiliate links. Shopify Help Center

That's attractive if you want to stay very close to Shopify's native ecosystem, but it's not the option I'd choose specifically because you want an API-first affiliate layer.

What I'd choose

For your stated architecture, my shortlist would be:

1. Refersion — best balance of Shopify + headless + API control.
2. impact.com — best for a larger/enterprise partnership program.
3. PartnerStack — best if this is really a partner/referral ecosystem rather than traditional ecommerce affiliates.
4. Shopify Collabs — best if minimizing custom infrastructure matters more than API flexibility.

One important architectural point: don't tie affiliate attribution directly to your frontend checkout implementation. Have your backend establish/maintain the affiliate attribution and then send the completed Shopify order/conversion to the affiliate platform server-side. Shopify explicitly supports headless storefronts where your frontend is independent of the commerce backend, so this separation fits the platform architecture well. Shopify Shopify

If you tell me whether you're B2C ecommerce or B2B, and roughly how many affiliates/orders per month, I can narrow this to 2–3 platforms and compare their API capabilities, tracking model, Shopify/headless implementation, payouts, pricing, and developer effort.

More importantly, Refersion just introduced a new API-first architecture. Its August 2026 API is the same API its own merchant application uses, with affiliate management, conversion management, order-based crediting, and webhooks exposed through the API. Refersion

That makes it a particularly good match if your architecture looks like:

Custom storefront
      │
      ├── affiliate/referral URL
      │
      ▼
Your frontend / backend
      │
      ├── Shopify Storefront API
      │
      └── Refersion API
              │
              ├── affiliates
              ├── conversions
              └── webhooks

Refersion also supports server-side order tracking, which is preferable for a headless implementation because you don't want affiliate attribution to depend entirely on client-side JavaScript. Refersion

refersion.dev

2. impact.com — best if you need enterprise partnership capabilities

I'd put impact.com on the shortlist if you're going beyond a straightforward affiliate program—for example, affiliates + influencers + strategic partners + media partners, sophisticated attribution, multiple commission structures, etc.

Its API-oriented model is well suited to a custom commerce stack, although I'd evaluate the implementation effort and pricing against Refersion before committing.

impact.com

3. PartnerStack — excellent API, but depends on your business model

PartnerStack has a genuine REST Partner API and Vendor API, giving developers programmatic control over partners, rewards, customers, and related objects. PartnerStack PartnerStack

I'd favor it if your "affiliate" program is really closer to a partner/referral ecosystem, particularly B2B/SaaS. For a consumer Shopify store where the main requirement is "affiliate sends customer → customer buys product → commission gets attributed," I'd investigate Refersion and impact.com first.

docs.partnerstack.com

4. Shopify Collabs — easiest, but less API-first

Collabs can work with custom storefronts, but Shopify's own documentation says custom storefronts need to send Shopify page-view events and handle redirects/discount routes for personalized affiliate links.

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate platforms that expose APIs/webhooks and let you control tracking rather than relying on Shopify theme/app scripts.

Best options

1. impact.com — probably the safest enterprise choice

impact.com's model is well suited if your storefront isn't using Shopify's Liquid theme. You can keep the affiliate/partner logic in your own application and communicate with the platform through APIs.

I'd consider it if you need:

• Affiliate links and custom attribution
• Influencer/creator partnerships in addition to traditional affiliates
• Custom conversion events
• Automated partner payouts
• Multiple partner types
• Enterprise-grade reporting

Your architecture could look roughly like:

Affiliate link → Custom storefront → your tracking layer → Shopify checkout/order → conversion event → impact.com

The important point is that Shopify remains your commerce system while the affiliate platform handles partner attribution.

2. Everflow — excellent if your developers want control

Everflow is particularly interesting for a technical/headless implementation. Its Shopify integration advertises full API access and white-label capabilities, along with affiliate/influencer tracking, custom commissions and real-time tracking. Shopify App Store

I'd put Everflow ahead of most alternatives if your requirements include:

• Server-side conversion tracking
• Custom attribution logic
• Multiple traffic/partner sources
• Your own affiliate portal/UI
• Detailed event and performance data
• API-driven integration rather than installing frontend scripts

For a genuinely custom storefront, this is probably the one I'd have your engineering team evaluate first alongside impact.com.

3. Shopify Collabs — worth considering if simplicity matters

There's a surprisingly important distinction here: Shopify itself supports affiliate links on custom storefronts, but you have to implement some storefront-side requirements.

Shopify says Collabs can work with custom storefronts provided you handle things like page-view events, URL redirects, and the /discount route. Shopify Help Center

So if your affiliate program is relatively straightforward, Collabs could save considerable integration work.

The downside is that you're accepting more of Shopify's affiliate-program architecture rather than having an independent affiliate platform.

What I'd choose

For your particular architecture:

Enterprise / broad partner program: → impact.com

Developer-controlled, API-heavy implementation: → Everflow

SaaS/B2B referrals: → PartnerStack

Simple Shopify-native affiliate program: → Shopify Collabs

Maximum customization / essentially building your own affiliate infrastructure: → TUNE

One architectural point is especially important: don't assume that "has a Shopify app" means "works well with headless." Shopify's Storefront API is explicitly designed for custom storefronts and can run independently of the standard Shopify frontend. Shopify Help Center Shopify Your affiliate platform therefore needs to support custom-domain link handling, browser/server-side tracking, conversion APIs/webhooks, and attribution independent of Liquid/theme scripts.

If you tell me your expected monthly orders, affiliate count, AOV, and whether checkout is Shopify Checkout or a completely custom checkout, I can narrow this to the 2–3 platforms I'd actually shortlist, including integration architecture and likely pricing.

Yes. For a headless Shopify + custom storefront, I’d prioritize platforms with a genuine API/server-side tracking model rather than ones that depend on a Shopify theme/app.

Best fits

1. Refersion — probably the strongest match

Refersion explicitly documents headless Shopify integrations, including Shopify's GraphQL Storefront API, JS Buy SDK/API-based implementations, cart attributes, and cross-domain tracking. They acknowledge that headless implementations require some custom developer work. Refersion Help Center

More importantly, Refersion just released API v2026-08 in August 2026. It's the API their own merchant application uses, exposing affiliates, conversions, orders, clicks, offers, promotion methods, and webhooks. Refersion

That makes the architecture you want fairly natural:

Custom storefront → your backend → Shopify → Refersion API/webhooks

rather than:

Custom storefront → Shopify theme/app → affiliate platform

refersion.com

2. impact.com — strongest enterprise option

impact.com has a much broader partnership-management capability and exposes APIs for partners, programs, contracts, conversions, tracking links, promo codes, reporting, etc. GitHub

However, there's a significant Shopify caveat: impact.com's documented Shopify integration currently says the storefront must be hosted on Shopify and that custom shopping experiences aren't supported through that integration. Impact Integrations

So I wouldn't choose impact.com based on its Shopify app for your architecture. I'd evaluate it specifically as an API-based/custom implementation and confirm the required attribution flow with their technical team.

integrations.impact.com

3. PartnerStack

PartnerStack has a proper vendor REST API with resource-oriented endpoints and test/production credentials. PartnerStack

I'd put it higher if you're doing B2B partnerships, referrals, resellers, or SaaS-style partner programs. For a traditional consumer/e-commerce affiliate program tied tightly to Shopify orders, Refersion is the more obvious candidate.

docs.partnerstack.com

4. Awin

Awin supports server-to-server tracking and other tracking mechanisms, but its Shopify documentation specifically warns that its Shopify app has only been validated with standard Shopify themes. Awin Help Center

So again, I'd investigate the direct tracking/API route, not assume the Shopify app will work with your storefront.

help.awin.com

What I'd shortlist

For your specific setup, I'd start with:

1. Refersion → easiest architectural match
2. impact.com → best if you need enterprise-scale affiliate + creator + partnership management
3. PartnerStack → best if the program is more partner/referral/B2B oriented
4. Awin → best when access to a large established affiliate network is a major requirement

One particularly important requirement to put in the RFP is server-side conversion attribution. Your custom storefront shouldn't have to depend on a Shopify Liquid theme, Shopify app pixel, or a client-side JavaScript snippet to establish the commission. Shopify's own documentation confirms that a headless storefront can be completely custom while using the Storefront API as the commerce layer. Shopify Help Center Shopify

If you tell me whether you're B2C or B2B, approximate monthly orders, and whether affiliates need deep links/coupons/influencer tracking, I can narrow this to 2–3 platforms and compare their APIs, attribution model, Shopify headless implementation, webhooks, commission rules, and pricing.

Yes. For a headless Shopify + custom storefront, I’d prioritize platforms where affiliate tracking can be implemented through APIs/server-side events rather than relying on a Shopify theme/app script.

Best fits

1. Everflow — strongest technical fit

developers.everflow.io

Everflow exposes a REST API covering network management, affiliates, advertisers, offers, tracking and reporting. Its Shopify integration can also track affiliate/influencer partnerships. Everflow API Shopify App Store

For your architecture, I'd look at Everflow if you want your storefront/application to own the customer experience and have affiliate attribution operate as an independent service.

Good fit if you need:

• Custom referral-link handling
• Server-side conversion tracking
• APIs for affiliates, offers, commissions and reporting
• Webhooks/postbacks
• Multiple storefronts or channels
• Potentially a custom affiliate portal/UI

2. Refersion — particularly interesting for Shopify

refersion.com

Refersion explicitly documents headless Shopify integrations, including Shopify's GraphQL Storefront API, Shopify API/JS Buy SDK, cart attributes and cross-domain tracking. It notes that headless implementations require additional developer work rather than simply installing the Shopify app. Refersion Help Center Refersion Help Center

Even more relevant: Refersion just released API v2026-08, which it describes as the API used by its own merchant application and now available to outside developers. Refersion

So if your requirement is essentially:

"We want Shopify to remain our commerce backend, but our frontend and customer journey are completely custom."

I'd put Refersion very high on the shortlist.

3. impact.com — strongest enterprise option

impact.com

impact.com has extensive API/integration capabilities—its documentation says integrations can be built through REST/GraphQL APIs, webhooks, SFTP or GTM, alongside 150+ prebuilt connectors. Impact

However, there's an important distinction: its standard Shopify integration currently expects the storefront/landing page to be hosted on Shopify and says custom shopping experiences aren't supported by that integration. Impact Integrations

That doesn't necessarily rule impact.com out—you'd want to evaluate its API/direct tracking implementation rather than its standard Shopify app.

My recommendation

For your specific architecture, I'd shortlist:

1. Everflow → if engineering flexibility and API control are the priority
2. Refersion → if Shopify compatibility and relatively straightforward affiliate operations are the priority
3. impact.com → if you're building a larger enterprise partner ecosystem spanning affiliates, influencers, creators, publishers, etc.

One particularly important architectural question is where the conversion event is generated. With a headless Shopify setup, I'd want the affiliate platform to support something like:

Affiliate click → custom storefront → Shopify checkout → order created → server-side conversion event → affiliate attribution

rather than depending on a JavaScript pixel being present in the Shopify theme.

If you tell me your frontend stack (Next.js, Hydrogen, Remix, etc.) and whether checkout is Shopify-hosted or fully custom, I can narrow this down to the 2–3 platforms that will integrate cleanly and outline the actual API architecture.

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate/partner platforms where tracking, conversion attribution, partner management, and reporting can be driven through APIs rather than relying on a Shopify theme/app.

Best fits

1. Everflow — probably my first choice

everflow.io

Everflow is particularly well suited to what you're describing. Its platform is explicitly API-first, with full API access for pushing/pulling platform data and building custom solutions. It also has a Shopify integration, while supporting custom tracking and broader integrations. Everflow Shopify App Store

That makes it attractive if your architecture looks something like:

Custom storefront → your backend/tracking layer → Everflow → Shopify

rather than:

Shopify theme → affiliate app → checkout

You can also keep your own affiliate UI/workflows and use Everflow as the underlying attribution and partner-management engine.

2. PartnerStack — excellent API, but more partner-program oriented

partnerstack.com

PartnerStack has a proper REST API covering customers, transactions, deals, leads, partnerships, webhooks, and other core objects. PartnerStack PartnerStack

I'd consider it if your "affiliates" are really partners, referrals, ambassadors, agencies, or B2B partners. For a conventional high-volume ecommerce affiliate program, I'd lean toward Everflow instead.

3. Awin — strong network, but watch the headless implementation

awin.com

Awin supports server-to-server tracking, conversion tracking, product-level tracking, custom parameters, and deduplication. Awin Help Center

However, Awin's Shopify app is validated against standard Shopify themes, so I wouldn't choose the app as the foundation of a custom headless implementation. Their server-side capabilities are much more interesting for your architecture. Awin Help Center

4. impact.com — worth evaluating for enterprise

impact.com

I'd put impact.com on the shortlist if you're looking beyond traditional affiliates into creator/influencer, referral, media, and strategic partnerships. It tends to make more sense when partnership management is becoming a broader growth channel rather than simply an affiliate program.

What I'd require technically

For your particular setup, I wouldn't evaluate platforms primarily on whether they have a "Shopify app." I'd ask each vendor whether they support:

• Server-side conversion tracking / S2S
• REST APIs and webhooks
• Passing your own click ID / sub-ID through the custom storefront
• Attribution against a Shopify order ID
• Coupon/code-based attribution
• Deep-link generation through API
• Product/catalog feeds through API
• Custom commission rules
• Deduplication with your other marketing attribution
• First-party tracking that doesn't depend on Shopify theme scripts
• Ability to operate without Liquid/theme modification
• Support for Shopify's headless checkout flow
• Ability to reconcile affiliate conversions against Shopify orders

This matters because Shopify explicitly supports custom storefronts through its Storefront API, with the storefront and commerce backend operating independently. Shopify Help Center Shopify

My initial ranking for your architecture:

Everflow → impact.com → PartnerStack → Awin

If you tell me whether you're B2C ecommerce, B2B, or both, approximate order volume, and whether you need affiliate recruitment/network access or just the tracking/commission infrastructure, I can narrow this to 2–3 platforms and compare their APIs, Shopify integration architecture, pricing, and implementation effort.

Custom storefront → your backend/tracking layer → Everflow → Shopify

rather than:

Shopify theme → affiliate app → checkout

You can also keep your own affiliate UI/workflows and use Everflow as the underlying attribution and partner-management engine.

2. PartnerStack — excellent API, but more partner-program oriented

partnerstack.com

PartnerStack has a proper REST API covering customers, transactions, deals, leads, partnerships, webhooks, and other core objects. PartnerStack PartnerStack

I'd consider it if your "affiliates" are really partners, referrals, ambassadors, agencies, or B2B partners. For a conventional high-volume ecommerce affiliate program, I'd lean toward Everflow instead.

3. Awin — strong network, but watch the headless implementation

awin.com

Awin supports server-to-server tracking, conversion tracking, product-level tracking, custom parameters, and deduplication. help.awin.com

However, Awin's Shopify app is validated against standard Shopify themes, so I wouldn't choose the app as the foundation of a custom headless implementation. Their server-side capabilities are much more interesting for your architecture. help.awin.com

4. impact.com — worth evaluating for enterprise

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate platforms that can handle tracking and conversions independently of Shopify’s native theme/app layer.

Best fits

My first choice would be Everflow. Its platform is explicitly API-first, with REST APIs covering network management, affiliates, advertisers, offers and reporting, plus webhooks and JavaScript tracking. It also specifically advertises connecting shopping-cart data and supporting Shopify with extensibility. Everflow API Everflow

developers.everflow.io

Why I'd be cautious with the Shopify apps

The important distinction is "supports Shopify" vs. "supports headless Shopify."

For example, impact.com's standard Shopify integration currently says the store landing page must be hosted on Shopify and explicitly says custom shopping experiences aren't supported by that integration. Impact Integrations

Similarly, Awin's Shopify documentation says its Shopify app has been validated with standard Shopify themes, which isn't the architecture you're describing. It does, however, support server-to-server tracking and custom parameters, which can make a custom integration viable. Awin Help Center

Shopify itself is well suited to this architecture: its Storefront API is designed for custom storefronts and Shopify explicitly supports bringing your own frontend/technology stack. Shopify Shopify

Architecture I'd recommend

For your setup, I'd aim for:

Affiliate platform → affiliate click → your custom storefront → Shopify Storefront API → checkout/order → server-side conversion event → affiliate platform

Rather than:

Affiliate platform → Shopify theme/app → Shopify checkout

That gives you control over attribution and avoids making the affiliate system dependent on Liquid/theme functionality.

Everflow is particularly interesting because its API includes advertiser/network-level APIs, webhooks, and client-side JavaScript tracking, so you can build the attribution layer into your own frontend/backend rather than relying on a Shopify plugin. Everflow API

If you're looking for a more conventional affiliate/creator platform rather than an attribution infrastructure layer, impact.com would be my second platform to evaluate.

impact.com

For a B2B SaaS-style referral program, PartnerStack is also worth considering; its Partner API is REST-based and gives programmatic control over partner/reward data. PartnerStack

partnerstack.com

Bottom line: if "API-first + headless Shopify + completely custom storefront" is the primary requirement, I'd shortlist Everflow → impact.com → Awin, with PartnerStack moving up the list if this is primarily a B2B referral/partner program.

If you tell me whether you need affiliate recruitment/network access, influencer/creator partnerships, or just affiliate tracking + commissions, I can narrow this to the 2–3 strongest options and compare their APIs, webhooks, Shopify compatibility, pricing model, and implementation effort.

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate platforms that can track conversions through APIs/server-side events rather than relying on a Shopify theme/app snippet.

Strongest options

My shortlist

1. Refersion — probably the easiest Shopify/headless choice

Refersion explicitly documents headless Shopify integrations, including GraphQL Storefront API, Shopify API/JS Buy SDK approaches, cart attributes, and cross-domain tracking. They also state that orders can be tracked through their API when a standard ecommerce integration doesn't fit. Refersion Help Center Refersion

That makes it particularly interesting if your architecture is:

Custom frontend → Shopify Storefront API → Shopify checkout

rather than a conventional Shopify Liquid storefront.

refersion.com

2. Everflow — best if you want the affiliate system to be infrastructure rather than a Shopify app

Everflow has a substantial API surface, including affiliate APIs, reporting, offers, postbacks, and marketplace functionality. Everflow API

I'd lean toward Everflow if you're building a sophisticated system where your own backend needs to control things like:

• affiliate/partner onboarding
• tracking IDs and attribution
• server-side conversion events
• custom commission logic
• postbacks/webhooks
• reporting
• multiple brands or storefronts
• non-Shopify sales channels

everflow.io

3. impact.com — strongest enterprise/composable option

If you're expecting the program to expand beyond traditional affiliates into creators, influencers, referral partners, and other partnership types, impact.com is worth evaluating. Its architecture is considerably more enterprise-oriented than typical Shopify affiliate apps.

impact.com

Important architectural point

Your Shopify setup itself isn't the obstacle. Shopify explicitly supports custom storefronts through its Storefront API, and the API is designed to work with arbitrary frontend stacks. Shopify Shopify

The key question for the affiliate platform is:

Can we record the affiliate click/identity on our custom frontend and subsequently send a server-side conversion containing the Shopify order ID, revenue, customer/order data, and attribution information?

That's much more important than whether the vendor has a "Shopify app."

For example, your architecture could look roughly like:

Affiliate link
      ↓
Custom storefront
      ↓
Capture affiliate click / partner ID
      ↓
Cookie or first-party session
      ↓
Shopify Storefront API
      ↓
Shopify Checkout
      ↓
Order created
      ↓
Your backend/webhook
      ↓
Affiliate platform Conversion API
      ↓
Commission + attribution

This avoids making your affiliate system dependent on Shopify's Liquid/theme layer.

What I'd choose

For a normal-to-large Shopify brand with a custom frontend, I'd evaluate Refersion vs. Everflow first.

• Refersion → simpler, Shopify-oriented, explicitly supports headless Shopify.
• Everflow → more powerful if you're building a serious custom partner/affiliate infrastructure.
• impact.com → best if you're thinking enterprise partnerships/creators in addition to affiliates.

If you tell me your frontend stack (Next.js/Hydrogen/etc.), Shopify checkout setup, approximate monthly orders, and whether you need influencer/creator tracking, I can narrow this to the best 2–3 and compare their APIs, webhooks, attribution model, Shopify compatibility, commission rules, and estimated implementation effort.

impact.com

Important architectural point

Your Shopify setup itself isn't the obstacle. Shopify explicitly supports custom storefronts through its Storefront API, and the API is designed to work with arbitrary frontend stacks. Shopify Shopify

The key question for the affiliate platform is:

Can we record the affiliate click/identity on our custom frontend and subsequently send a server-side conversion containing the Shopify order ID, revenue, customer/order data, and attribution information?

That's much more important than whether the vendor has a "Shopify app."

For example, your architecture could look roughly like:

Affiliate link
      ↓
Custom storefront
      ↓
Capture affiliate click / partner ID
      ↓
Cookie or first-party session
      ↓
Shopify Storefront API
      ↓
Shopify Checkout
      ↓
Order created
      ↓
Your backend/webhook
      ↓
Affiliate platform Conversion API
      ↓
Commission + attribution

This avoids making your affiliate system dependent on Shopify's Liquid/theme layer.

What I'd choose

For a normal-to-large Shopify brand with a custom frontend, I'd evaluate Refersion vs. Everflow first.

• Refersion → simpler, Shopify-oriented, explicitly supports headless Shopify.
• Everflow → more powerful if you're building a serious custom partner/affiliate infrastructure.
• impact.com → best if you're thinking enterprise partnerships/creators in addition to affiliates.

If you tell me your frontend stack (Next.js/Hydrogen/etc.), Shopify checkout setup, approximate monthly orders, and whether you need influencer/creator tracking, I can narrow this to the best 2–3 and compare their APIs, webhooks, attribution model, Shopify compatibility, commission rules, and estimated implementation effort.

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate platforms that can track conversions and manage affiliates without depending on Shopify’s native storefront/app UI.

Best fits

1. everflow.io — strongest technical fit

I'd put Everflow at the top of the shortlist if your engineering team wants maximum control.

It provides APIs for affiliate/partner management, reporting, offers, tracking and postbacks, and its Shopify integration supports affiliate/influencer tracking. Its Shopify listing specifically advertises full API access and white-label capabilities. Everflow API Shopify App Store

This is particularly attractive if your architecture is:

Custom storefront → Shopify Storefront API → Shopify checkout/order → Everflow tracking

rather than:

Shopify theme → Shopify affiliate app

2. refersion.com — easiest Shopify-oriented option

Refersion explicitly documents headless Shopify integrations, including setups using the GraphQL Storefront API, Shopify JS Buy SDK/API-based integrations, cart attributes, and cross-domain tracking. Refersion Help Center

It also supports using its API for order tracking when the platform isn't directly supported. Refersion

So if you want something relatively Shopify-native while still accommodating your custom frontend, Refersion is probably the lowest-complexity choice.

3. partnerstack.com — excellent API, but different emphasis

PartnerStack has a substantial REST API covering customers, transactions, deals, leads, partnerships, actions and webhooks. PartnerStack PartnerStack

I'd consider it if your "affiliates" are really partners, resellers, referral partners, SaaS integrations, or B2B channels. For a conventional DTC affiliate program attached to a Shopify store, I'd lean toward Everflow or Refersion instead.

One important architectural point

Shopify itself is well suited to this architecture: the Storefront API is designed specifically for custom/headless storefronts and is framework-agnostic. Shopify Shopify

I'd therefore avoid choosing an affiliate platform solely because it has a good Shopify App Store integration. The key question is whether it lets your backend explicitly communicate:

• affiliate/referral click → visitor/session
• affiliate ID/sub-ID → cart/customer
• completed Shopify order → conversion
• order value → commission
• refunds/cancellations → commission reversal
• attribution → webhook/API
• custom checkout/domain → tracking

My shortlist would be Everflow + Refersion first, with impact.com added if you need a much broader enterprise partnership/creator ecosystem.

If you tell me whether you're DTC, B2B, or both, your approximate monthly order volume, and whether checkout stays on Shopify or is also custom, I can narrow this to 2–3 platforms and compare their APIs, tracking architecture, pricing, and implementation effort.

It provides APIs for affiliate/partner management, reporting, offers, tracking and postbacks, and its Shopify integration supports affiliate/influencer tracking. Its Shopify listing specifically advertises full API access and white-label capabilities. Everflow API Shopify App Store

This is particularly attractive if your architecture is:

Custom storefront → Shopify Storefront API → Shopify checkout/order → Everflow tracking

rather than:

Shopify theme → Shopify affiliate app

2. refersion.com — easiest Shopify-oriented option

Refersion explicitly documents headless Shopify integrations, including setups using the GraphQL Storefront API, Shopify JS Buy SDK/API-based integrations, cart attributes, and cross-domain tracking. Refersion Help Center

It also supports using its API for order tracking when the platform isn't directly supported. Refersion

So if you want something relatively Shopify-native while still accommodating your custom frontend, Refersion is probably the lowest-complexity choice.

3. partnerstack.com — excellent API, but different emphasis

PartnerStack has a substantial REST API covering customers, transactions, deals, leads, partnerships, actions and webhooks. docs.partnerstack.com docs.partnerstack.com

I'd consider it if your "affiliates" are really partners, resellers, referral partners, SaaS integrations, or B2B channels. For a conventional DTC affiliate program attached to a Shopify store, I'd lean toward Everflow or Refersion instead.

One important architectural point

Shopify itself is well suited to this architecture: the Storefront API is designed specifically for custom/headless storefronts and is framework-agnostic.

Yes. For a headless Shopify + custom storefront, I’d prioritize an affiliate platform that exposes tracking, conversions, commissions, partner data, and webhooks through APIs, rather than one that depends primarily on a Shopify theme/app.

Best fits

My first choice: Everflow

Everflow is probably the strongest match if API-first is a hard requirement.

Its API surface includes advertiser, affiliate, marketplace and network APIs, plus webhooks and a JavaScript SDK for click/conversion/impression tracking. Everflow API Everflow API

That makes an architecture like this practical:

Affiliate link
      ↓
Custom storefront
      ↓
Your tracking layer / Everflow JS SDK
      ↓
Shopify Storefront API
      ↓
Shopify checkout/order
      ↓
Conversion event → Everflow API
      ↓
Commission + affiliate reporting

This is preferable to trying to force a traditional Shopify affiliate app into your storefront.

Refersion is worth considering

Refersion explicitly supports Shopify and says that if your ecommerce platform isn't supported, you can use its API to track orders. It also offers custom integrations on its Enterprise plan. Refersion

So I'd consider it if you want simpler Shopify/DTC operations and don't need Everflow's breadth.

Awin is interesting for network reach

Awin has REST APIs for transactions, reporting, promotions, link building, and performance data. Awin Help Center

However, its current Shopify app is only validated for standard Shopify themes, which is a warning sign for your architecture. Awin does support server-to-server tracking, so you'd want to investigate an API/S2S implementation rather than relying on the Shopify app. Awin Help Center

I would be cautious with Impact

impact.com has powerful APIs, but its current Shopify integration documentation explicitly says the Shopify store must have its landing page hosted on Shopify and that custom shopping experiences aren't supported. Impact Integrations

That's directly at odds with a fully custom/headless storefront, so I wouldn't select it based on its standard Shopify integration.

Recommended shortlist

For your particular architecture, I'd rank them:

1. Everflow — best if engineering flexibility/API control is the priority.
2. Refersion — best if Shopify/DTC simplicity is more important.
3. Awin — best if access to a large established affiliate network is important.
4. PartnerStack — excellent API, but I'd choose it primarily for B2B/SaaS-style partner programs rather than conventional Shopify DTC affiliates. Its Vendor API and Partner API are REST-based. PartnerStack PartnerStack
5. Impact — powerful enterprise platform, but its documented Shopify/headless limitation makes it less attractive here.

One important point: Shopify itself supports headless storefronts through its Storefront API and treats headless storefronts as sales channels for attribution/analytics, so you don't necessarily need your affiliate platform to have a native Shopify storefront plugin. shopify.dev shopify.dev

If you tell me (1) B2C vs B2B, (2) approximate monthly orders, and (3) whether you need affiliate recruitment/network discovery or just tracking + commissions, I can narrow this to the best 2–3 platforms and map out the exact integration architecture/API flow.

Its API surface includes advertiser, affiliate, marketplace and network APIs, plus webhooks and a JavaScript SDK for click/conversion/impression tracking. Everflow API Everflow API

That makes an architecture like this practical:

Affiliate link
      ↓
Custom storefront
      ↓
Your tracking layer / Everflow JS SDK
      ↓
Shopify Storefront API
      ↓
Shopify checkout/order
      ↓
Conversion event → Everflow API
      ↓
Commission + affiliate reporting

This is preferable to trying to force a traditional Shopify affiliate app into your storefront.

Refersion is worth considering

Refersion explicitly supports Shopify and says that if your ecommerce platform isn't supported, you can use its API to track orders. It also offers custom integrations on its Enterprise plan. Refersion

So I'd consider it if you want simpler Shopify/DTC operations and don't need Everflow's breadth.

Awin is interesting for network reach

Awin has REST APIs for transactions, reporting, promotions, link building, and performance data. help.awin.com

However, its current Shopify app is only validated for standard Shopify themes, which is a warning sign for your architecture. Awin does support server-to-server tracking, so you'd want to investigate an API/S2S implementation rather than relying on the Shopify app. help.awin.com

I would be cautious with Impact

impact.com has powerful APIs, but its current Shopify integration documentation explicitly says the Shopify store must have its landing page hosted on Shopify and that custom shopping experiences aren't supported.

That's directly at odds with a fully custom/headless storefront, so I wouldn't select it based on its standard Shopify integration.

Recommended shortlist

For your particular architecture, I'd rank them:

Yes. For a headless Shopify + custom storefront, I’d prioritize platforms with a real API/SDK tracking layer rather than ones that depend primarily on a Shopify App Store integration.

Best fits

My first choice would be Everflow. Its documentation describes the platform as API-first, with a Network API, advertiser/affiliate APIs, webhooks, and a JavaScript SDK for client-side click, conversion and impression tracking. It also has a Shopify integration if you want to use Shopify-specific functionality alongside your custom implementation. Everflow API Everflow

developers.everflow.io

Refersion is probably the strongest alternative for a DTC Shopify brand. Importantly, Refersion explicitly documents headless Shopify integrations, including GraphQL Storefront API, Shopify API/JS Buy SDK implementations, cart-attribute tracking, and cross-domain tracking. Their documentation also says custom headless implementations may require developer involvement. Refersion Help Center Refersion

support.refersion.com

One I'd be cautious about

impact.com is very capable, but its current Shopify integration documentation specifically says that the standard integration requires the storefront landing page to be hosted on Shopify and that custom shopping experiences aren't currently supported through that integration. Impact

That doesn't necessarily rule out an enterprise/custom implementation, but I'd put it behind Everflow and Refersion for your architecture.

How I'd architect it

With your setup, I'd keep Shopify responsible for commerce and use the affiliate platform as an attribution/partner layer:

Affiliate link → Custom storefront → affiliate click ID → cart/checkout → Shopify order → server-side conversion event → affiliate platform

That avoids making the affiliate platform dependent on Shopify's frontend. Shopify itself supports custom storefronts through the Storefront API, so this architecture is consistent with Shopify's headless model. Shopify Help Center Shopify

Shortlist:

1. Everflow — best if engineering flexibility/API control is the priority.
2. Refersion — best if you want a more DTC-oriented affiliate product with documented headless Shopify support.
3. impact.com — consider if you're enterprise-scale and need its broader partnership ecosystem.

If you tell me whether you need affiliate recruitment/marketplace, influencer/creator tracking, coupon attribution, recurring commissions, or just link → Shopify order attribution, I can narrow this to the best 2–3 and compare their APIs, tracking model, and likely implementation effort.

My first choice would be Everflow. Its documentation describes the platform as API-first, with a Network API, advertiser/affiliate APIs, webhooks, and a JavaScript SDK for client-side click, conversion and impression tracking. It also has a Shopify integration if you want to use Shopify-specific functionality alongside your custom implementation. Everflow API Everflow

developers.everflow.io

Refersion is probably the strongest alternative for a DTC Shopify brand. Importantly, Refersion explicitly documents headless Shopify integrations, including GraphQL Storefront API, Shopify API/JS Buy SDK implementations, cart-attribute tracking, and cross-domain tracking. Their documentation also says custom headless implementations may require developer involvement. support.refersion.com refersion.com

support.refersion.com

One I'd be cautious about

impact.com is very capable, but its current Shopify integration documentation specifically says that the standard integration requires the storefront landing page to be hosted on Shopify and that custom shopping experiences aren't currently supported through that integration.

That doesn't necessarily rule out an enterprise/custom implementation, but I'd put it behind Everflow and Refersion for your architecture.

How I'd architect it

With your setup, I'd keep Shopify responsible for commerce and use the affiliate platform as an attribution/partner layer:

Affiliate link → Custom storefront → affiliate click ID → cart/checkout → Shopify order → server-side conversion event → affiliate platform

That avoids making the affiliate platform dependent on Shopify's frontend. Shopify itself supports custom storefronts through the Storefront API, so this architecture is consistent with Shopify's headless model.

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate/partnership platforms that expose tracking, conversions, partner management, and reporting through APIs rather than relying on a Shopify theme/app integration.

Best fits

My shortlist

1. Partnerize — strongest pure API-first candidate

Partnerize actually describes itself as an API-first solution, with its web application built on top of its APIs. That's unusually aligned with a custom storefront architecture. Partnerize API Documentation Partnerize

I'd look at this if your requirements include:

• Your own affiliate UI/workflows
• Server-side conversion reporting
• Custom attribution logic
• Deep-link generation
• Partner/commission management through your backend
• Multiple storefronts/brands/markets
• Feeding affiliate data into your own data warehouse

2. Everflow — probably the most developer-friendly alternative

Everflow's API is REST/JSON-based and covers network management, advertisers, affiliates, offers and reporting. It also provides webhooks and a JavaScript SDK for client-side click/conversion/impression tracking. Everflow API Everflow API

That makes it particularly interesting if your architecture looks something like:

Custom Storefront → Your Backend → Shopify

with

Your Backend ↔ Everflow

and conversion events ultimately originating from Shopify orders.

3. Awin — strong if network reach matters

Awin has substantial API coverage and, importantly for headless commerce, a server-to-server Conversion API. Awin Help Center Awin Help Center

One caveat: Awin explicitly says its Shopify app has only been validated with standard Shopify themes. For your architecture, I'd treat the Shopify app as optional and architect around their APIs/S2S tracking instead. Awin Help Center

One important architectural point

You don't need your affiliate platform to understand your Shopify storefront.

Shopify's headless architecture is specifically designed so the storefront can be completely separate from Shopify's backend; the Storefront API supplies the commerce layer to your custom frontend. Shopify Help Center Shopify

So I'd design the integration roughly as:

Affiliate click
      ↓
Affiliate platform
      ↓
Custom storefront
      ↓
Your tracking/session layer
      ↓
Shopify Storefront API
      ↓
Shopify checkout/order
      ↓
Order/conversion event
      ↓
Affiliate platform Conversion API / S2S

That is preferable to installing a conventional Shopify affiliate app and hoping its theme scripts work with your headless frontend.

If I were choosing purely for your stated requirement, I'd start with Partnerize and Everflow, then compare Awin/Impact based on the affiliate network and partner types you need.

If you tell me whether you're B2C/DTC or B2B, approximate monthly order volume, and whether you need affiliate recruitment/network access vs. just the tracking/commission infrastructure, I can narrow this to the 2–3 platforms that make the most sense.

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate platforms that let you implement tracking, attribution, partner management, and conversion events through APIs rather than depending on a Shopify theme/app.

Shopify itself confirms that custom storefronts can be built independently of the Shopify frontend and connected through the Storefront API, so the affiliate layer should similarly be decoupled from the storefront. Shopify Help Center Shopify

Best fits

1. Everflow — probably my first choice for a custom stack

everflow.io

Everflow is particularly interesting for your architecture because it explicitly describes its platform as API-first and provides full API access for pushing/pulling data and building custom integrations. It also supports Shopify tracking while remaining extensible beyond the standard Shopify implementation. Everflow

That makes it a strong fit if you want something like:

Custom storefront → your backend → Everflow tracking/attribution → Shopify

rather than:

Shopify theme → affiliate app → tracking script

I'd put Everflow at the top if your engineering team wants control over the customer journey and attribution implementation.

2. Impact — strongest all-around enterprise option

impact.com

Impact is another strong candidate. Shopify specifically lists Impact's REST API as an affiliate API option, with capabilities around conversion tracking, link generation, workflow automation, and performance data. Shopify

It's especially compelling if "affiliate" eventually expands into creators, influencers, strategic partnerships, and referral partners, rather than just traditional affiliate publishers.

3. Awin — good if publisher-network access matters

awin.com

Awin has REST APIs for transactions, reporting, offers, link creation, and publisher performance. Awin Help Center

One important caveat for your architecture: Awin's Shopify app is validated against standard Shopify themes, and Awin explicitly doesn't guarantee compatibility with other themes. However, it supports server-to-server tracking, so I'd investigate the API/S2S route rather than building your headless implementation around its Shopify app. Awin Help Center

4. PartnerStack — excellent API, but different sweet spot

partnerstack.com

PartnerStack has both partner and vendor REST APIs, exposing things such as customers, transactions, deals, leads, partnerships, and webhooks. PartnerStack PartnerStack

I'd favor it if you're building a B2B/SaaS-style partner or referral program. For a conventional consumer ecommerce affiliate program, I'd investigate Everflow, Impact, and Awin first.

What I'd choose

For your specific architecture, my shortlist would be:

1. Everflow — best if API control and custom attribution are the priority.
2. Impact — best if you want affiliate + creator + partnership capabilities in one platform.
3. Awin — best if access to an established publisher network is a major requirement.
4. PartnerStack — best if this is really a partner/referral ecosystem rather than conventional ecommerce affiliates.

The key technical requirement I'd put into an RFP is server-side conversion attribution. Don't choose a platform merely because it has a "Shopify integration." Your custom storefront means you want the affiliate platform to expose APIs/webhooks for at least:

• click/referral ID generation and persistence
• affiliate link/deep-link generation
• conversion/order event ingestion
• order ID and line-item data
• commission calculation
• refunds/cancellations
• attribution validation/deduplication
• partner/publisher management
• reporting API
• webhooks
• first-party/server-side tracking

That lets your application own the critical flow while Shopify remains the commerce backend. Shopify's current headless architecture explicitly supports bringing your own stack and integrating other backend systems around the Storefront API. Shopify Shopify

If you tell me your approximate GMV/order volume, B2C vs. B2B, and whether you need creator/influencer recruitment or just affiliate tracking, I can narrow this to 2–3 platforms and compare their APIs, pricing, Shopify/headless implementation, and attribution model.

That makes it a strong fit if you want something like:

Custom storefront → your backend → Everflow tracking/attribution → Shopify

rather than:

Shopify theme → affiliate app → tracking script

I'd put Everflow at the top if your engineering team wants control over the customer journey and attribution implementation.

2. Impact — strongest all-around enterprise option

impact.com

Impact is another strong candidate. Shopify specifically lists Impact's REST API as an affiliate API option, with capabilities around conversion tracking, link generation, workflow automation, and performance data. Shopify

It's especially compelling if "affiliate" eventually expands into creators, influencers, strategic partnerships, and referral partners, rather than just traditional affiliate publishers.

3. Awin — good if publisher-network access matters

awin.com

Awin has REST APIs for transactions, reporting, offers, link creation, and publisher performance. Awin Help Center

One important caveat for your architecture: Awin's Shopify app is validated against standard Shopify themes, and Awin explicitly doesn't guarantee compatibility with other themes. However, it supports server-to-server tracking, so I'd investigate the API/S2S route rather than building your headless implementation around its Shopify app. Awin Help Center

4. PartnerStack — excellent API, but different sweet spot

partnerstack.com

PartnerStack has both partner and vendor REST APIs, exposing things such as customers, transactions, deals, leads, partnerships, and webhooks.

I'd favor it if you're building a B2B/SaaS-style partner or referral program. For a conventional consumer ecommerce affiliate program, I'd investigate Everflow, Impact, and Awin first.

What I'd choose

For your specific architecture, my shortlist would be:

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate platforms that can track conversions through APIs/server-to-server rather than assuming a standard Shopify theme/app integration.

Best fits

1. Partnerize — strongest technical fit.
Partnerize explicitly describes its platform as API-first, with integrations typically requiring only a few hours of development. It supports first-party, server-to-server, batch, and mobile tracking. Partnerize Partnerize

partnerize.com

2. impact.com — strongest overall platform.
It supports REST/GraphQL APIs, webhooks and other integration methods, and its tracking can be implemented via APIs rather than relying solely on storefront JavaScript. It also has a Shopify integration, so you can combine native Shopify data with custom integration where needed. Impact impact.com

impact.com

3. Refersion — good if you want something more DTC-oriented.
Refersion specifically documents headless Shopify integrations, including Shopify Storefront API/GraphQL-based setups, Shopify API integrations, cart attributes, and cross-domain tracking. Its REST API v2 can also be used to integrate affiliate/conversion workflows. Refersion Help Center Refersion

refersion.com

4. Awin — viable, but I'd validate your architecture carefully.
Awin has advertiser APIs and supports S2S tracking, but its Shopify app documentation says the app itself is validated only against standard Shopify themes. For a genuinely custom storefront, you'd likely want to use its APIs/tracking infrastructure rather than depend on the Shopify app. Awin Help Center Awin Help Center

awin.com

What I'd choose

For your particular architecture, my shortlist would be:

Partnerize → impact.com → Refersion

If you're building a fairly sophisticated custom storefront, I'd lean Partnerize or impact.com. If you're a DTC operation and want less enterprise overhead, Refersion is worth a serious look.

The key architectural question isn't just "does it integrate with Shopify?" It's whether the platform can handle this flow cleanly:

Affiliate link → custom storefront → Shopify Storefront API/cart → Shopify checkout → order/conversion event → affiliate platform API/S2S → commission

Shopify's Storefront API is explicitly designed to power custom storefronts, so the affiliate platform needs to sit alongside that architecture rather than expecting Liquid/theme-based tracking. shopify.dev

If you tell me your frontend stack (Next.js, Hydrogen, Remix, etc.) and whether checkout remains on Shopify or is also customized, I can narrow this to the 2–3 platforms with the cleanest integration architecture.

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate platforms with a real tracking/API layer rather than platforms whose Shopify integration assumes a standard theme.

Shopify itself supports headless storefronts through the Storefront API, and its Headless channel supports custom storefronts and order attribution. Shopify Shopify

Best fits

1. Everflow — strongest technical choice

Everflow is probably the first platform I'd evaluate for your architecture. Its API is REST-based and exposes network management, advertisers, affiliates, offers, reporting and tracking; it also provides webhooks and a JavaScript SDK for client-side click/conversion/impression tracking. Everflow API

That makes it well suited to an architecture like:

Custom storefront → your tracking layer → Shopify Storefront API → Everflow API/webhooks

Rather than trying to force your custom storefront through a Shopify theme/app integration.

developers.everflow.io

2. impact.com — strongest if you want affiliate + creators

Impact has a substantial REST API and supports affiliate, creator and partnership workflows. Shopify's current documentation specifically notes that impact.com has API integration in addition to its Shopify app. Shopify

Important caveat: its Shopify app currently says that custom shopping experiences aren't supported when the store landing page is hosted externally. Impact Integrations

So for your use case, I'd investigate API/server-side integration, rather than assuming the standard Shopify app will work with your storefront.

integrations.impact.com

3. Awin — strong network + API

Awin has advertiser APIs for transactions, reporting, promotions and performance data. Its API documentation explicitly positions the APIs for deeper integration and workflow automation. Awin Help Center

However, Awin's Shopify app is validated against standard Shopify themes, so I wouldn't choose the app as the integration mechanism for your headless storefront. Its APIs/S2S tracking are the more relevant pieces for you. Awin Help Center

help.awin.com

4. PartnerStack — very API-friendly, especially for B2B

PartnerStack has separate Partner and Vendor REST APIs, with resource-oriented endpoints and API authentication. PartnerStack PartnerStack

I'd consider it particularly if your "affiliate" program is really a partner/referral/reseller program, rather than a traditional ecommerce publisher network.

docs.partnerstack.com

My shortlist for your architecture

If this is a consumer ecommerce Shopify store, I'd rank them:

1. Everflow — best pure API/technical fit
2. impact.com — best broader partnership/creator ecosystem
3. Awin — best if access to its publisher network is important
4. PartnerStack — move this up if you're primarily B2B/referral

The key architectural question isn't just "does it have a Shopify integration?" It's "can we track the affiliate click and attribute a Shopify order without relying on Shopify's Online Store theme/runtime?"

For a headless implementation, I'd specifically require:

• Server-side conversion API or S2S postback
• Click/deep-link tracking that works on your custom domain
• Ability to pass affiliate/sub-ID data through your custom checkout flow
• Shopify order/customer identifiers available for conversion reconciliation
• Webhooks
• REST/GraphQL APIs for affiliates, offers, commissions and reporting
• Support for your consent/privacy architecture
• No dependency on Shopify theme pixels or Liquid
• Ability to handle Shopify's current checkout architecture

Everflow is the one I'd put through a technical POC first. Its combination of REST APIs, webhooks and client-side tracking gives you the least reason to compromise your existing headless architecture. Everflow API

If you tell me whether this is DTC ecommerce, B2B, or marketplace, and what your storefront stack is (e.g. Next.js/Hydrogen, React, Nuxt, custom backend), I can narrow this to 2–3 platforms and map the exact integration architecture.

Custom storefront → your tracking layer → Shopify Storefront API → Everflow API/webhooks

Rather than trying to force your custom storefront through a Shopify theme/app integration.

developers.everflow.io

2. impact.com — strongest if you want affiliate + creators

Impact has a substantial REST API and supports affiliate, creator and partnership workflows. Shopify's current documentation specifically notes that impact.com has API integration in addition to its Shopify app. Shopify

Important caveat: its Shopify app currently says that custom shopping experiences aren't supported when the store landing page is hosted externally. Impact Integrations

So for your use case, I'd investigate API/server-side integration, rather than assuming the standard Shopify app will work with your storefront.

integrations.impact.com

3. Awin — strong network + API

Awin has advertiser APIs for transactions, reporting, promotions and performance data. Its API documentation explicitly positions the APIs for deeper integration and workflow automation. Awin Help Center

However, Awin's Shopify app is validated against standard Shopify themes, so I wouldn't choose the app as the integration mechanism for your headless storefront. Its APIs/S2S tracking are the more relevant pieces for you. Awin Help Center

help.awin.com

4. PartnerStack — very API-friendly, especially for B2B

PartnerStack has separate Partner and Vendor REST APIs, with resource-oriented endpoints and API authentication.

I'd consider it particularly if your "affiliate" program is really a partner/referral/reseller program, rather than a traditional ecommerce publisher network.

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate platforms where tracking, conversions, partner management, and reporting can be integrated through APIs/server-side events rather than relying on a Shopify theme/app.

Best fits

Partnerize is probably the first platform I'd evaluate. Its documentation explicitly describes the product as API-first, with REST APIs for programmatic integration, and its integration ecosystem includes Shopify. Partnerize API Documentation Partnerize

Everflow is another particularly strong candidate if your team wants to own more of the technical implementation. It provides APIs for advertisers/affiliates, webhooks for real-time events, and a JavaScript SDK for click, conversion, and impression tracking. Everflow API Everflow API

Awin can work, especially if you want its affiliate network, but I'd treat it as a more implementation-dependent option. Awin's current documentation says its Shopify app has only been validated with standard Shopify themes and specifically warns that headless implementations may require additional configuration or an alternative tracking implementation. It does, however, support server-to-server tracking and APIs. Awin Help Center Awin Help Center

I would not make impact.com the first choice for this architecture. Its current Shopify integration documentation explicitly says the integration requires the storefront landing page to be hosted on Shopify and that custom shopping experiences aren't currently supported. Impact

What I'd recommend architecturally

For your setup, don't make the affiliate platform dependent on the Shopify frontend. Instead:

Affiliate click → custom storefront → your tracking layer → Shopify checkout/order → server-side conversion event → affiliate platform

That lets your frontend remain completely decoupled. Shopify itself supports this model: its Storefront API is specifically designed for custom storefronts and can be used with essentially any frontend stack. Shopify Shopify

I'd specifically evaluate each vendor on:

• Server-to-server conversion tracking
• Ability to pass an affiliate click/reference ID through your custom storefront and Shopify cart
• Webhooks for conversion/status changes
• APIs for creating/managing partners, offers and commissions
• SubID/custom parameter support
• Coupon-code attribution
• New-vs-returning customer commission rules
• Deduplication between affiliate, paid media and other channels
• Shopify order/customer data access
• Support for subscriptions/refunds/cancellations
• Consent/privacy handling
• Whether their API exposes everything you need, rather than requiring their Shopify app

My shortlist

If you're choosing three vendors to put through a technical proof of concept, I'd use:

1. Partnerize — strongest overall fit for an enterprise API-first partnership program.
2. Everflow — strongest if engineering flexibility/control is the priority.
3. Awin — worth evaluating if access to its publisher network is strategically important.

Shopify's own documentation reinforces the key architectural point: custom storefronts are intended to connect your frontend to Shopify's commerce backend through APIs, rather than depending on the standard Online Store/Liquid experience. Shopify Help Center Shopify

If you tell me your approximate GMV, number of affiliates, B2C vs. B2B, and whether you need influencer/creator partnerships in addition to traditional affiliates, I can narrow this to the best 2–3 and compare pricing, APIs, tracking architecture, Shopify compatibility, and implementation effort.

For your setup, don't make the affiliate platform dependent on the Shopify frontend. Instead:

Affiliate click → custom storefront → your tracking layer → Shopify checkout/order → server-side conversion event → affiliate platform

That lets your frontend remain completely decoupled. Shopify itself supports this model: its Storefront API is specifically designed for custom storefronts and can be used with essentially any frontend stack.

I'd specifically evaluate each vendor on:

Yes. For a headless Shopify + custom storefront, I’d prioritize platforms where affiliate attribution can be implemented independently of Shopify’s theme/app layer.

Best fits

1. Refersion — probably the closest match

refersion.com explicitly documents headless Shopify integrations, including GraphQL Storefront API, Shopify API/JS SDK approaches, cart attributes, and cross-domain tracking. They also state that their API can be used to track orders when a platform isn't directly supported. Refersion Help Center Refersion

That's important because your architecture can essentially be:

Custom storefront → Shopify Storefront API → Shopify checkout/order → Refersion attribution

rather than forcing the affiliate software to control your frontend.

Refersion also supports first-party tracking and custom domains, which are attractive for a custom storefront. Refersion

I'd put this at #1 if your primary goal is a conventional affiliate/creator program around a Shopify DTC business.

2. PartnerStack — strongest API philosophy

partnerstack.com has a genuine REST Partner API designed to give developers control over the integration. Its API exposes partner, reward and related program resources rather than assuming that your storefront is a standard Shopify theme. PartnerStack

I'd favor it if you're thinking beyond traditional affiliates toward:

• referral partners
• agencies
• resellers
• SaaS-style partner programs
• custom partner portals
• programmatic partner onboarding

The caveat is that PartnerStack isn't as Shopify/DTC-centric as Refersion, so you'll want to validate the exact ecommerce conversion/commission workflow you need.

3. CJ Affiliate — good if network reach matters

cj.com has APIs plus dedicated non-browser-based/API tracking, alongside conventional site tracking. CJ's developer documentation specifically describes API tracking for advertisers. CJ Developer

This becomes particularly interesting if you want access to a large established publisher/affiliate network rather than primarily running your own recruited creator/affiliate base.

4. Awin — another strong enterprise option

awin.com supports server-to-server tracking and has advertiser APIs for transaction and performance data. Awin Help Center Awin Help Center

For headless Shopify, I'd favor the API/S2S integration path, not its standard Shopify app: Awin itself notes that its Shopify app has only been validated with standard Shopify themes. Awin Help Center

One I'd put lower: impact.com

impact.com is powerful and very API/integration friendly generally, but its current Shopify integration documentation explicitly says custom shopping experiences aren't supported and expects the store landing page to be hosted on Shopify. Impact Integrations

So I wouldn't select it because you have a headless architecture without first getting their solutions team to confirm your exact implementation.

My shortlist for your architecture

If I were evaluating this for your team, I'd do:

1. Refersion → best Shopify + headless + DTC combination
2. PartnerStack → best if "affiliate" is really becoming a broader partner platform
3. CJ Affiliate → best if publisher/network scale is a major requirement
4. Awin → strong enterprise/network alternative
5. impact.com → powerful, but I'd require architectural confirmation first

One important architectural point: Shopify itself is quite suitable for this setup. Shopify's Storefront API is explicitly intended to be the foundation for custom storefronts, so the affiliate platform doesn't need to own your frontend. Shopify Shopify

If you tell me (a) whether checkout remains Shopify-hosted, (b) whether you need influencer/creator management in addition to affiliates, and (c) approximate monthly order volume, I can narrow these down to the 2–3 platforms I'd actually put into an RFP, including API/tracking architecture and likely implementation complexity.

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate platforms that can track conversions without assuming the customer journey happens inside Shopify’s Liquid theme.

Best fits

My shortlist

1. UpPromote — probably the easiest fit

This is the one I'd investigate first if your goal is "affiliate SaaS + our own frontend + APIs." UpPromote provides an API for custom integrations and webhooks for referral events. More importantly, its third-party-store integration explicitly covers Hydrogen and custom headless stores, including tracking cart changes when you're using the Shopify Storefront API. docs.uppromote.com

UpPromote developer documentation

2. Refersion — strongest if your team wants a more programmable integration

Refersion specifically has documentation for headless Shopify and supports several approaches, including GraphQL Storefront API, Shopify API, cart attributes, and cross-domain tracking. The tradeoff is that Refersion says headless implementations are custom and may require developer involvement. support.refersion.com

Refersion headless Shopify documentation

3. Social Snowball — worth considering for influencer/creator-heavy programs

It has an explicit headless Shopify implementation. Your storefront needs to preserve the affiliate/referral parameter through the redirect, after which its script handles attribution. help.socialsnowball.io

One architectural point I'd insist on

Don't choose based solely on whether the vendor has a "Shopify app." Your architecture is essentially:

Affiliate link → custom storefront → Shopify Storefront API/cart → Shopify checkout → order → affiliate platform

Shopify itself explicitly supports this kind of architecture: the Storefront API is designed for custom storefronts, and the Headless channel provides API credentials, permissions, product publishing, and order attribution. shopify.dev

The affiliate platform therefore needs to handle at least:

• Click/referral ID capture on your custom domain
• Persistence of that ID through your SPA/SSR navigation
• Attribution to the Shopify cart/order
• Coupon/code-based attribution as a fallback
• Server-side conversion webhooks/API
• Refund/cancellation handling
• Multiple storefront/domain support
• Deep links to arbitrary product/content pages
• First-party tracking that doesn't depend entirely on third-party cookies

If you tell me your stack (e.g. Hydrogen/Remix, Next.js, Nuxt, custom React) and whether you need influencer recruitment/payouts or primarily affiliate attribution, I can narrow this to the 2–3 platforms that are genuinely appropriate and compare their APIs, tracking architecture, pricing, and Shopify limitations.

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate platforms where tracking and conversion events can be integrated independently of Shopify’s Liquid/theme layer.

Best fits

1. UpPromote — probably the easiest Shopify-native choice

UpPromote explicitly supports Hydrogen and custom headless stores through its third-party tracking integration. You can put its tracking code on your custom storefront and send cart updates using Shopify's Storefront API. docs.uppromote.com

It also has a public REST API and webhooks, including APIs for managing affiliates. aff-api.uppromote.com

UpPromote developer/API documentation

Best when: you want a relatively turnkey Shopify affiliate program but need your frontend to remain completely custom.

2. Refersion — good middle ground

Refersion explicitly documents headless Shopify integrations, including setups using the GraphQL Storefront API, Shopify JS Buy SDK/API integrations, cart attributes, and cross-domain tracking. They note that headless implementations require additional developer work. support.refersion.com

Refersion headless Shopify documentation

Best when: you want a conventional affiliate-management product and don't mind implementing the tracking layer yourself.

3. Everflow — my choice for a highly custom architecture

Everflow is considerably more API/platform-oriented than a typical Shopify affiliate app. Its API supports affiliate/partner operations, reporting, offers, postbacks, etc., and it has a Shopify integration as well. developers.everflow.io

Everflow developer documentation

Best when: you're building your own attribution/tracking architecture, expect multiple acquisition channels, or want the affiliate system to be an infrastructure component rather than just a Shopify app.

4. PartnerStack — strongest for partner programs

PartnerStack has a vendor REST API covering customers, transactions, deals, leads, partnerships and webhooks. docs.partnerstack.com

PartnerStack API documentation

I'd consider it particularly if your "affiliate" program is actually evolving toward partners, creators, referrals, resellers, or B2B partnerships.

One I'd avoid for this specific architecture

impact.com has a Shopify integration, but its current documentation explicitly says the Shopify integration requires the store landing page to be hosted on Shopify and that custom shopping experiences aren't supported. integrations.impact.com

So I wouldn't select it if your custom storefront is a hard requirement.

My shortlist

If I were evaluating this for your architecture, I'd test them in this order:

Everflow → UpPromote → Refersion → PartnerStack

The important architectural question isn't just "does it have an API?" It's whether you can do:

affiliate link → custom storefront → persistent attribution → Shopify Storefront API cart → Shopify checkout → server-side conversion event → commission

without relying on a Shopify theme script.

Shopify itself is well suited to this architecture: its Storefront API is framework-agnostic and intended specifically for custom storefronts. shopify.dev

If you tell me whether you need coupon-code attribution, affiliate links, influencer/creator tracking, or all three, I can narrow this to the best 2–3 platforms and compare their API/webhook capabilities, Shopify headless implementation, attribution model, and likely integration effort.

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate platforms with a server-to-server conversion API, flexible tracking, and webhooks—not platforms whose Shopify app assumes a standard Liquid storefront.

Best fits

Everflow stands out if your engineering team wants to own the integration. Its platform exposes a REST API covering network management, offers, affiliates, reporting, tracking, etc., and its Affiliate API supports things like postbacks and reporting. developers.everflow.io

Everflow API documentation

Refersion is particularly interesting if you're primarily a DTC Shopify brand. Refersion explicitly says headless Shopify requires additional integration beyond simply installing its Shopify app, and it provides an API for tracking orders/custom integrations. support.refersion.com

Refersion API & integrations

One I'd be cautious about

impact.com is a very capable enterprise affiliate/partnership platform, but its Shopify integration currently states that the store's landing page must be hosted on Shopify and that custom shopping experiences aren't supported. That's a significant mismatch for your architecture unless you're using a different integration path with impact. integrations.impact.com

What your integration should look like

For your setup, I'd architect it roughly as:

Affiliate link → custom storefront → attribution ID → your backend → Shopify order → affiliate conversion API

For example:

1. Affiliate sends traffic to yoursite.com/?ref=ABC123.
2. Your custom frontend captures ABC123.
3. Store it in a first-party cookie/session/server-side customer context.
4. Customer purchases through Shopify's Storefront API/checkout.
5. Your backend receives the completed-order event.
6. Backend calls the affiliate platform's conversion API with:
   • affiliate/referral ID
   • Shopify order ID
   • order value
   • commissionable amount
   • currency
   • customer/order metadata required for deduplication
7. Affiliate platform records the conversion and handles commission/reporting.

That's preferable to depending on a Shopify pixel or Liquid theme script. Shopify itself supports this kind of architecture: its Storefront API is explicitly designed for custom storefronts and is framework-agnostic. shopify.dev

My shortlist

If I were evaluating this for your team, I'd start with:

1. Everflow — if API control and custom attribution are the priority.
2. Refersion — if Shopify/DTC usability and affiliate-program management are the priority.
3. Awin — if access to a large established affiliate network is important; its Shopify integration also supports server-to-server tracking, although its Shopify app has compatibility limitations around standard themes. help.awin.com

One interesting alternative is Shopify Collabs: Shopify now documents a specific approach for personalized affiliate links on custom storefronts, but you have to implement page-view events, URL redirects, and the /discount route correctly. help.shopify.com

Bottom line: if "API-first" is a hard requirement, I'd put Everflow and Refersion at the top of the technical evaluation, with Everflow probably the stronger choice for a genuinely custom/headless architecture.

If you tell me whether you're using Hydrogen, Next.js, or another frontend, I can narrow this down to the 2–3 platforms whose APIs can actually support your attribution → Shopify order → commission flow, including the specific API/webhook capabilities to compare.

For a headless Shopify setup with a custom storefront, you’ll generally want an affiliate platform that can operate independently of Shopify’s theme/app layer and expose REST APIs, webhooks, SDKs, or server-side tracking. Shopify’s headless architecture already separates the storefront from commerce APIs, so the affiliate layer should fit into your backend/event pipeline rather than rely on Liquid theme snippets. shopify.dev

Here are the stronger API-friendly options:

My shortlist for a headless Shopify build

1. Impact.com

• Best if you expect:
  • many affiliates/creators
  • multiple commission models
  • international programs
  • agency/partner workflows
• Typical architecture:
  • storefront → Shopify checkout/order events → middleware → Impact API/webhooks

2. Everflow

• Best if your team wants more control over attribution.
• Strong fit when you have:
  • custom landing pages
  • paid acquisition + affiliate overlap
  • complex conversion events

3. TUNE

• Best if you want to embed affiliate functionality deeply into your own product experience.
• Good choice if your affiliate portal/UI will be custom-built.

Integration pattern I’d recommend

For a custom Shopify storefront:

1. Affiliate platform owns
   • affiliate IDs
   • tracking links
   • commission rules
   • payouts

2. Your backend owns
   • customer identity
   • order lifecycle
   • fraud rules
   • attribution reconciliation

3. Connect via:
   • Shopify webhooks (orders/create, refunds, cancellations)
   • affiliate platform conversion API
   • server-side tracking pixels/events
   • scheduled reconciliation jobs

Shopify’s Storefront API supports custom storefronts and headless implementations, so you can keep the storefront fully custom while integrating external systems through your application layer. shopify.dev

What I would avoid

• Affiliate apps that require installing JavaScript snippets into Shopify themes
• Platforms without:
  • conversion APIs
  • webhook support
  • custom commission logic
  • server-to-server tracking

If you share your stack (e.g., Next.js/Hydrogen, Remix, custom Node backend, checkout approach, B2C vs B2B, and expected affiliate volume), I can narrow this to the 2–3 best fits.

For a headless Shopify + custom storefront, you’ll want an affiliate platform that does not depend on Shopify theme scripts or Liquid checkout hooks. The key capabilities are:

• REST/GraphQL API or server-side conversion API
• Webhook support
• Ability to create/manage affiliate links via API
• Ability to ingest orders/conversions from your backend
• Custom affiliate dashboards or embeddable components
• Support for Shopify Storefront API / Hydrogen-style architectures (Shopify’s headless stack relies on APIs rather than a Shopify-rendered storefront). shopify.dev

Platforms worth evaluating:

For a fully custom storefront, I would shortlist:

1. Impact.com — enterprise-grade

Good if you need:

• influencer + affiliate + partner programs together
• complex commission rules
• automated partner onboarding
• large reporting requirements

2. Everflow — developer-first performance tracking

Good if your engineers want:

• API-controlled attribution
• custom funnels
• server-to-server conversion tracking
• granular reporting

3. Tapfiliate — simpler headless implementation

Good if you want:

• affiliate signup flows
• custom frontend experiences
• manageable API integration without enterprise overhead

4. Refersion — Shopify-native but workable

Refersion can support headless Shopify, but headless implementations usually require custom tracking integration rather than the standard Shopify app flow. support.refersion.com

Recommended architecture for your setup

A common headless pattern:

1. Affiliate link:

/landing-page?ref=creator123

2. Your storefront captures:

affiliate_id
campaign_id
cookie/session attribution

3. Customer purchases through Shopify checkout.

4. Your backend listens for Shopify order events and sends:

{
  "order_id": "12345",
  "amount": 149.00,
  "currency": "USD",
  "affiliate": "creator123"
}

to the affiliate platform’s conversion API.

5. Affiliate platform handles:
6. commission calculation
7. reporting
8. payouts
9. fraud rules

This server-to-server approach is generally more reliable than relying on storefront pixels in headless setups. overrideaff.com

If you tell me your stack (Hydrogen/React, Next.js, Vue, custom backend, Shopify Plus vs regular Shopify, subscription vs one-time purchases), I can narrow this to the best 2–3 options and the integration approach.

Yes. For a headless Shopify + custom storefront, I’d prioritize platforms where affiliate tracking can be implemented through APIs/server-side events rather than relying on a Shopify theme/app.

Best fits

My first choice: Everflow

Everflow is probably the strongest architectural match if your requirement is "our storefront is custom, so don't make us build around a Shopify app."

Everflow explicitly describes its platform as API-first, with APIs for managing offers, affiliates, advertisers and reporting, plus webhooks and a JavaScript SDK for click/conversion/impression tracking. developers.everflow.io

That makes it attractive if your architecture looks roughly like:

Custom storefront → Shopify Storefront API → Shopify checkout/orders → your backend → affiliate platform API

You can keep affiliate attribution and conversion logic in your own application layer rather than putting affiliate logic into a Liquid theme.

impact.com

impact.com is the stronger choice if you're looking for a broader partnership platform—affiliates + creators + influencers + strategic partners—rather than purely affiliate infrastructure.

It supports REST/GraphQL APIs and webhooks, and advertises 150+ prebuilt integrations. get.impact.com

Important caveat: impact.com's standard Shopify integration currently says that the store landing page must be hosted on Shopify and that custom shopping experiences aren't supported. integrations.impact.com

So I would not choose its Shopify app as the integration mechanism for your headless storefront. You'd want to validate an API/server-side implementation with their solutions team.

PartnerStack

PartnerStack has a solid REST API. Its Partner API gives you programmatic access to partner/reward data, while the Vendor API exposes core partner-program objects. docs.partnerstack.com

I'd consider it particularly if "affiliate" actually means referral/partner ecosystem for you—for example, agencies, resellers, ambassadors, or B2B partners. For a traditional high-volume consumer affiliate network, I'd lean toward Everflow or impact.com.

Awin

Awin is worth considering if access to an established affiliate network is important. It supports server-to-server tracking, custom parameters, product feeds and other tracking mechanisms. help.awin.com

However, its Shopify app is explicitly validated against standard Shopify themes, so I wouldn't assume the app itself is suitable for your headless frontend. help.awin.com

One important Shopify architectural point

Shopify's current headless architecture supports custom storefronts through the Storefront API, and Shopify treats a headless storefront as a channel for order attribution/analytics. shopify.dev

So I'd evaluate these vendors based on whether they can handle server-side conversion attribution against Shopify order events, rather than asking simply "Do you have a Shopify integration?"

For your situation, my shortlist would be:

1. Everflow — best technical/API fit
2. impact.com — best enterprise partner ecosystem
3. Awin — best if affiliate-network reach is a major requirement
4. PartnerStack — best if this is really a partner/referral program
5. Refersion — worth considering if you want Shopify simplicity over architectural flexibility

If you tell me your monthly order volume, whether checkout is Shopify Checkout, and whether you need an existing affiliate network or just affiliate-program management, I can narrow this to 2–3 options and compare their APIs, webhooks, attribution, deep links, coupon tracking, payouts, and headless Shopify implementation.

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate platforms that let you implement tracking and conversion attribution through APIs/server-side events rather than requiring a Shopify theme/app to control the storefront.

Best fits

My first two to evaluate would be Partnerize and Everflow.

1. Partnerize — strongest enterprise/API-first option

Partnerize explicitly describes its platform as API-first, with REST APIs and developer documentation. Its integrations are designed to expose partnership data to other systems rather than making you dependent on a particular storefront implementation. api-docs.partnerize.com

That makes it particularly attractive if your architecture looks roughly like:

Custom storefront → Shopify Storefront API → your backend/order system → Partnerize

You can keep affiliate logic out of the Shopify theme entirely and integrate it into your application/backend.

Partnerize API documentation

2. Everflow — probably the best developer-oriented choice

Everflow says the entire platform was built API-first, with APIs for pushing/pulling data and building custom solutions. It also has a Shopify integration, while supporting custom scripts for advanced tracking requirements. www.everflow.io

That combination is compelling for a headless build: you can use the Shopify integration where useful, but aren't forced to make the Shopify storefront the center of your implementation.

Everflow developer/API resources

3. Awin — good if affiliate-network reach matters

Awin has advertiser APIs for transaction data, reporting, transaction validation and, importantly for headless architectures, a Conversion API designed for server-to-server tracking. help.awin.com

The tradeoff is that some Awin API functionality is plan-dependent, and its standard Shopify integration is more app-oriented. help.awin.com

What I'd require technically

For your architecture, I'd make these requirements non-negotiable:

• Server-to-server conversion API — don't rely exclusively on browser pixels.
• Click ID / affiliate ID persistence — you need to carry attribution from the custom storefront through checkout.
• API/webhook access to conversions — useful for reconciliation and refunds/cancellations.
• Order ID / transaction ID support — map affiliate conversions back to Shopify orders.
• Deep-link generation — affiliates should be able to link directly to your custom URLs.
• Sub-ID/custom parameter support — useful for campaign, creator, placement and creative attribution.
• Coupon/code attribution — particularly important for creator partnerships.
• Refund/void/adjustment support — commission should ultimately reconcile against Shopify's actual order state.
• No dependency on Liquid/theme pixels — this is the big one for your setup.

Shopify itself supports custom storefronts through the Storefront API, and its Headless channel provides storefront-specific API credentials and channel-level order attribution, so the affiliate system should sit alongside that architecture rather than trying to own the storefront. shopify.dev

My shortlist

If I were selecting for a technical team:

1. Partnerize — best overall for enterprise partnership infrastructure and API-first architecture.
2. Everflow — best combination of API flexibility, developer experience and performance/affiliate tracking.
3. Awin — strongest consideration if access to Awin's established publisher network is a major requirement.
4. impact.com — worth evaluating if you want one platform spanning affiliates, creators, referrals and other partner types.

If you tell me (a) your approximate monthly order volume, (b) whether this is B2C or B2B, and (c) whether you need traditional affiliate-network publishers vs. primarily influencers/creators, I can narrow this to the 2–3 platforms I'd actually RFP, including API architecture, Shopify/headless implementation approach, pricing model, and key integration risks.

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate platforms that let you implement tracking and conversion attribution through APIs/server-side events rather than requiring a Shopify theme/app pixel.

Best fits

1. Everflow — my first choice

Everflow is probably the strongest fit if your requirement is "we own the storefront and want the affiliate platform to be an API/service behind it."

Everflow explicitly describes its platform as API-first, with REST APIs for managing offers, affiliates, reporting, tracking, etc. developers.everflow.io

It also has a Shopify integration, so you can connect Shopify on the backend while still retaining control over your frontend. Its Shopify offering supports affiliates, influencers and other partner types, with full API access and white-label capabilities. www.everflow.io

Architecture I'd consider:

Affiliate link → custom storefront → Shopify cart/checkout → server-side conversion event → Everflow

That avoids making your affiliate system dependent on Liquid/theme scripts.

2. PartnerStack — excellent if this is a partner/referral program

PartnerStack has a REST API designed specifically for vendors to integrate their partner programs. Its APIs expose customers, transactions, deals, leads, partnerships, rewards and webhooks. docs.partnerstack.com

I'd put PartnerStack ahead of Everflow if you're building something closer to a partner/referral ecosystem—for example, agencies, creators, resellers or B2B partners—rather than a traditional high-volume consumer affiliate network.

3. Awin — good if network reach matters

Awin has advertiser APIs for transactions, reporting, offers and validation, and supports server-to-server tracking. help.awin.comhelp.awin.com

The important caveat is that Awin's Shopify app is validated for standard Shopify themes, and Awin explicitly doesn't guarantee compatibility with other themes. help.awin.comhelp.awin.com

So for your architecture I'd investigate the API/S2S integration, rather than assume the Shopify app will work with the custom storefront.

4. impact.com — powerful, but I'd be cautious

impact.com is a major enterprise partnership platform, but its current Shopify integration documentation says the Shopify store's landing page must be hosted on Shopify and that custom shopping experiences aren't currently supported. integrations.impact.com

That's a significant red flag for your specific architecture. I wouldn't choose impact.com based solely on its Shopify integration; you'd want their technical team to confirm that your exact headless implementation can use their alternative tracking/API mechanisms.

My shortlist

If I were evaluating this for your stack, I'd rank them:

1. Everflow — best overall technical fit
2. PartnerStack — best if partners/referrals are more important than traditional affiliate-network functionality
3. Awin — best if access to a large established affiliate network is important
4. impact.com — powerful enterprise option, but verify headless support before committing

Shopify itself explicitly supports custom storefronts through its Storefront API, with the frontend separated from Shopify's commerce backend. help.shopify.com That makes an API/S2S affiliate architecture a much better fit than choosing a platform primarily because it has a Shopify theme plugin.

If you tell me your storefront stack (e.g. Next.js/Hydrogen), whether checkout is Shopify Checkout, and whether you need affiliate recruitment/network access vs. just tracking + commissions, I can narrow this to 2–3 platforms and compare their tracking architecture, APIs/webhooks, Shopify compatibility, attribution, payouts, and estimated implementation effort.

Yes. For a headless Shopify + custom storefront, I’d prioritize platforms that can track conversions through APIs/server-side events rather than relying on a Shopify theme/app script.

Best fits

My first choice for your architecture would be Refersion. Their documentation specifically covers headless Shopify, including GraphQL Storefront API, Shopify API/JS Buy SDK integrations, cart-attribute tracking, cross-domain tracking, and other custom approaches. They also explicitly say you can use their API to track orders when your platform isn't directly supported. support.refersion.com

Refersion

One important caveat with impact.com

I would not assume the standard impact.com Shopify integration works for your setup. Their current Shopify integration documentation explicitly says the store must be hosted on Shopify and that custom shopping experiences aren't currently supported. integrations.impact.com

impact.com

That doesn't necessarily rule impact.com out—you could investigate a custom/server-side integration—but I wouldn't choose it based on its Shopify app.

What I'd require from the vendor

For your custom storefront, I'd make these requirements non-negotiable:

1. Server-side conversion API — your backend should be able to tell the affiliate platform that an order occurred.
2. Click/referral ID persistence — capture the affiliate ID on the custom frontend and carry it through your cart/checkout.
3. Shopify order ID support — conversion events should map cleanly back to the Shopify order.
4. Webhooks — commission changes, refunds, cancellations, etc. should flow back to your systems.
5. API access to affiliates, commissions and conversions — don't make your operations team live entirely in the vendor dashboard.
6. Cross-domain attribution — particularly important if your custom storefront and Shopify checkout live on different domains/subdomains.
7. Coupon-code attribution as a fallback.
8. Refund/reversal handling — critical for accurate commissions.

Shopify itself is well suited to this architecture: its Storefront API is framework-agnostic and can be used from essentially any frontend stack, while Shopify's headless tooling is designed for custom storefronts. shopify.dev

Bottom line

If you're a DTC brand running a custom/headless Shopify frontend, I'd shortlist:

1. Refersion — strongest Shopify/headless fit
2. Everflow — strongest if you want maximum control over tracking/attribution
3. Awin — strongest if access to a large affiliate network is a priority
4. impact.com — strongest enterprise option, but requires careful validation of the custom integration

If you tell me your frontend stack (Next.js/Hydrogen/etc.), checkout setup, and whether you need an affiliate network or just software to run your own affiliate program, I can narrow this to 2–3 options and compare their APIs, webhooks, attribution model, Shopify compatibility, and likely implementation effort.

Yes. For a headless Shopify + custom storefront, I’d prioritize platforms where affiliate tracking and conversion attribution can be implemented through APIs/server-side events rather than relying on a Shopify theme/app.

Best fits

My first choice would be Everflow. Its documentation explicitly describes the platform as API-first, with REST APIs covering affiliates, offers, advertisers, reporting, tracking and webhooks. It also provides JavaScript SDKs for click/conversion/impression tracking. www.everflow.io

Everflow API documentation

That makes it particularly attractive if your architecture looks something like:

Custom storefront → Shopify Storefront API → your backend → Everflow tracking/conversion API

rather than:

Shopify theme → affiliate app → Shopify checkout

One important caveat with Impact

impact.com has strong APIs and Shopify support, but its current Shopify integration documentation explicitly says the Shopify integration expects the storefront landing page to be hosted on Shopify and that custom shopping experiences aren't currently supported. integrations.impact.com

So I wouldn't choose Impact solely because it has a Shopify app. You'd want their implementation team to confirm the exact API/server-side architecture for your headless setup.

Awin

Awin is also technically viable. Its APIs can pull transactions/reporting and create promotions, and its documentation specifically positions the APIs for deeper integrations and workflow automation. help.awin.com

However, its Shopify app has a similar caveat: Awin says it has been validated against standard Shopify themes and doesn't guarantee compatibility with other themes. help.awin.com For a headless build, I'd use its API/S2S capabilities rather than depending on the app.

What I'd shortlist

1. Everflow — strongest technical fit
Choose this if your engineering team wants control over attribution, tracking, webhooks, partner data and custom storefront behavior.

2. Awin — strongest if affiliate-network reach matters
Good option if you want access to an established publisher ecosystem in addition to the API capabilities.

3. Impact — strongest enterprise option
Excellent if you need a broader partnership/creator/affiliate platform, but I'd get explicit confirmation that your headless architecture is supported before committing.

4. Refersion / Tapfiliate — simpler alternatives
Potentially easier for a conventional Shopify affiliate program, but I'd put them behind Everflow if API-first/headless is a core architectural requirement.

One thing I'd specifically test in vendor demos is whether the platform can create/identify an affiliate click on your custom frontend and then receive a server-side conversion containing the Shopify order ID, line items, discounts, customer/order value, and affiliate ID. That's much more important for your architecture than whether the vendor has a Shopify App Store listing.

If you tell me roughly your monthly order volume and whether you need influencer/creator management in addition to traditional affiliates, I can narrow this to 2–3 platforms and compare their APIs, tracking architecture, Shopify compatibility, and likely pricing.

Yes. For a headless Shopify + custom storefront, I’d prioritize platforms that expose tracking and conversion APIs rather than relying on a Shopify theme/app embed.

Best fits

1. Everflow — strongest technical fit

Everflow is probably the first platform I'd evaluate for your architecture. Its entire platform is API-oriented, with REST APIs, webhooks, and a JavaScript SDK for click/conversion/impression tracking. developers.everflow.io

Importantly for your setup, Everflow's Shopify integration supports custom scripts and server-side data transfer, and its reconciliation can match Shopify cart IDs to Everflow transaction IDs when cookies are lost or checkout crosses contexts. helpdesk.everflow.io

Everflow

2. Refersion — good if you want a more ecommerce-oriented product

Refersion explicitly documents headless Shopify integrations, including Shopify's GraphQL Storefront API, JS Buy SDK/API-based integrations, cart attributes, and cross-domain tracking. They note that headless implementations require additional developer work. support.refersion.com

It also exposes REST and GraphQL APIs, and its documentation specifically says you can use the API to track orders when your ecommerce platform isn't directly supported. www.refersion.com

Refersion

3. impact.com — powerful, but I'd investigate the headless limitation first

impact.com has strong APIs and a broad partnership platform, but its current Shopify integration documentation explicitly says the standard integration expects the store's landing page to be hosted on Shopify and that custom shopping experiences aren't currently supported through that integration. integrations.impact.com

So I wouldn't choose it for a headless architecture without first getting their technical team to confirm the exact implementation.

impact.com

My recommendation

For a genuinely custom storefront, I'd shortlist:

Everflow → Refersion → impact.com

If your developers want to own the customer journey and send affiliate attribution/conversion data through your own backend, Everflow is the strongest match. If you want something more ecommerce/DTC-oriented with less infrastructure work, Refersion is very compelling.

One architectural point I'd insist on: don't make affiliate attribution depend on Shopify's frontend/theme. Ideally your flow is:

Affiliate link → custom storefront → persistent attribution ID → Shopify checkout → order webhook/backend → affiliate platform conversion API

That keeps the affiliate layer compatible with your headless frontend and lets you change the storefront without rebuilding the affiliate program.

If you tell me your storefront stack (e.g. Next.js/Hydrogen/React) and whether checkout stays on Shopify Checkout or a custom checkout, I can narrow this to the 2–3 platforms that will actually work with your architecture.

Yes. For a headless Shopify + custom storefront, I’d prioritize platforms that can track conversions through server-side APIs rather than requiring a Shopify theme/app integration.

Best fits

My first two would be Tapfiliate and Everflow.

• Tapfiliate is particularly attractive for your architecture because it explicitly supports custom-coded applications through its REST API. Its API can handle clicks, conversions, commissions, refunds, coupon-code attribution, etc. support.tapfiliate.com
• Everflow is stronger if you need sophisticated attribution, postbacks, multiple traffic sources, or a more enterprise-grade tracking layer. Its API exposes affiliate/offer/reporting functionality. developers.everflow.io
• impact.com is very capable and has extensive APIs, but there's an important caveat: its standard Shopify integration currently says the storefront must be hosted on Shopify and that custom shopping experiences aren't supported. For a truly headless implementation, you'd want to validate the custom/API implementation with them rather than relying on their Shopify app. integrations.impact.com
• Refersion is worth considering if your priority is minimizing Shopify-specific implementation work, but I'd put it behind Tapfiliate/Everflow for a genuinely API-driven architecture.

How I'd architect it

Your custom storefront should own the customer experience while the affiliate platform becomes the attribution/commission system:

Affiliate link
      ↓
Custom storefront
      ↓
Capture affiliate/referral ID
      ↓
Persist attribution
      ↓
Shopify Storefront API / Checkout
      ↓
Order completed
      ↓
Your backend / webhook
      ↓
Affiliate platform API
      ↓
Conversion + commission

That approach fits Shopify's headless model: Shopify's Storefront API is specifically intended to provide the commerce primitives for custom storefronts. shopify.dev

If you're choosing today:
Tapfiliate = easiest API-first DTC implementation.
Everflow = best if attribution/tracking sophistication is more important.
impact.com = strongest enterprise ecosystem, but I'd get explicit confirmation on the headless architecture before committing.

If you tell me your monthly order volume, affiliate count, and whether you need influencer/creator management, I can narrow this to 2–3 platforms and compare their APIs, Shopify compatibility, tracking model, payouts, and likely implementation effort.

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate platforms that can track conversions through APIs/server-side events rather than relying on a Shopify theme/app pixel.

Best fits

1. Everflow — my first choice for a genuinely API-first architecture.
Everflow explicitly describes its platform as API-first, with APIs for pushing/pulling platform data, and it supports Shopify tracking. Its API model makes it particularly attractive when your storefront isn't the conventional Shopify frontend. www.everflow.io

Everflow developer/API documentation

2. Refersion — probably the easiest Shopify-oriented option.
Refersion specifically documents headless Shopify integrations, including GraphQL Storefront API, Shopify API/JS Buy SDK, cart-attribute tracking, and custom integrations. They acknowledge that headless implementations require some developer work. support.refersion.com

It also supports sending order data through its API/webhooks, which is useful if your checkout/order flow doesn't expose the traditional Shopify tracking environment. www.refersion.com

Refersion headless Shopify documentation

3. impact.com — worth evaluating if you're building a serious partner program.
I'd put this on the shortlist if you expect affiliates to expand into influencers, creators, strategic partnerships, etc. It's more of an enterprise partnership platform than a lightweight Shopify affiliate app.

What I'd choose

If your architecture is roughly:

Custom frontend → Shopify Storefront API → Shopify checkout → Shopify orders

I'd shortlist Everflow vs. Refersion, with Everflow winning if API flexibility is the primary requirement.

The important architectural question isn't actually whether the platform has a Shopify app. It's whether you can do:

1. Affiliate clicks → your custom storefront
2. Persist affiliate/click identifier through your custom frontend/cart
3. Complete Shopify checkout
4. Receive the resulting Shopify order server-side
5. Send the order + affiliate attribution to the affiliate platform through an API/webhook
6. Handle refunds/cancellations and commission reversals

That's particularly important with headless because Shopify itself describes custom storefronts as an independent frontend connected to Shopify's commerce backend via APIs. help.shopify.com

My ranking for your specific requirement:

Everflow → Refersion → impact.com → Partnerize → Shopify-native apps

If you tell me your frontend stack (Next.js/Hydrogen/etc.), whether checkout stays on Shopify, and approximate affiliate volume, I can narrow this to 2–3 platforms and compare their actual API/event architecture, tracking method, Shopify compatibility, pricing, and implementation effort.

Yes. For a headless Shopify + custom storefront, I’d prioritize affiliate platforms that let you control tracking and conversion events through APIs rather than relying on a Shopify theme/app script.

Best fits

1. Refersion — probably the first one I'd evaluate

Refersion explicitly documents headless Shopify integrations, including setups using the Shopify GraphQL Storefront API, JS Buy SDK/API-based integrations, cart attributes, and cross-domain tracking. They note that headless implementations require additional developer work rather than simply installing their Shopify app. support.refersion.com

That's a good match if your architecture is roughly:

Custom frontend → Shopify Storefront API → Shopify checkout → Refersion tracking

The important advantage is that you're not forced to rebuild your storefront around their Shopify app.

Refersion platform

2. impact.com — strongest if you want an enterprise-grade partner platform

impact.com has REST APIs and supports affiliate, creator, and broader partnership workflows. Shopify's own 2026 affiliate-API overview specifically notes that impact.com's APIs can be used for conversion tracking, link generation, and performance data. www.shopify.com

However, there's an important caveat: impact.com's standard Shopify integration currently says the storefront must be hosted on Shopify and that custom shopping experiences aren't supported through that particular integration. integrations.impact.com

So for your architecture, I'd ask impact specifically about an API/server-side implementation, rather than assuming the normal Shopify app will work.

impact.com

3. PartnerStack — excellent API, but different use case

PartnerStack has a proper vendor REST API for managing core partner-program objects. docs.partnerstack.com

I'd consider it if your "affiliate program" is actually evolving into a partner ecosystem—resellers, referral partners, agencies, SaaS integrations, recurring commissions, etc.

For a conventional DTC Shopify store, though, I'd generally put Refersion or impact.com ahead of PartnerStack.

PartnerStack

What I'd shortlist for your architecture

If you're building something like:

Custom Next.js / React storefront
             │
             ▼
     Shopify Storefront API
             │
             ▼
      Shopify Checkout
             │
             ▼
     Orders / Webhooks
             │
             ▼
     Affiliate Platform API

I'd evaluate them in this order:

1. Refersion → easiest fit for Shopify/DTC + headless
2. impact.com → best if you need enterprise partnerships/creators/network scale
3. Awin → worth considering if access to a large publisher network is important
4. PartnerStack → move this higher if you're building a broader partner/referral ecosystem

One thing I'd specifically validate during demos is server-side conversion attribution. With a custom storefront, you don't want the affiliate platform to depend on a Shopify theme pixel or browser-side script. Shopify itself supports fully custom storefronts through its Storefront API, so the affiliate system should ideally accept your conversion/order events independently of the frontend. shopify.dev

If you tell me your storefront stack (Next.js/Hydrogen/etc.), checkout flow, and whether you need influencer/creator affiliates or traditional affiliates, I can narrow this to the 2–3 platforms that are actually viable architecturally.

Yes. With a headless Shopify architecture, you should prioritize affiliate platforms that are API-first rather than those that rely on Shopify Liquid theme snippets or storefront scripts. Shopify's Storefront API and Headless channel are designed to support custom storefronts, so your affiliate platform should integrate through APIs, webhooks, or server-side tracking rather than theme injection. shopify.dev

Here's how the leading options compare:

1. Impact.com (Recommended for enterprise)

Pros:

• Comprehensive REST APIs
• Webhooks
• Server-to-server conversion tracking
• Supports custom attribution models
• Handles affiliates, influencers, and partnerships in one platform

Best if you have:

• Custom frontend
• Custom checkout logic
• Multiple sales channels
• International affiliates

2. Everflow (Excellent API)

One of the most developer-friendly options.

Features include:

• Complete REST API
• Postback tracking
• Webhooks
• Server-side events
• Flexible attribution

Works very well with:

• Next.js
• Hydrogen
• Remix
• React
• Custom Node backends

Many headless commerce teams choose Everflow because almost everything is exposed through APIs.

3. PartnerStack

Excellent if you're planning to grow beyond traditional affiliates.

Supports:

• Affiliates
• Agencies
• Referral partners
• Influencers

Strong API coverage and enterprise-grade integrations.

4. Tolt

A newer platform with a modern API.

Advantages:

• Easy implementation
• REST API
• Webhooks
• Stripe integration
• Good developer experience

A good fit for smaller DTC brands that still want API-driven workflows.

Architecture for Headless Shopify

The ideal integration looks like this:

Affiliate Link
      ↓
Custom Frontend (React / Next.js / Hydrogen)
      ↓
Storefront API
      ↓
Checkout
      ↓
Webhook
      ↓
Affiliate Platform API
      ↓
Commission Recorded

Instead of JavaScript snippets embedded in Shopify themes, conversions are recorded from your backend using webhooks or server-side API calls.

Features to prioritize

For a custom storefront, look for:

• ✅ REST or GraphQL APIs
• ✅ Server-side conversion tracking
• ✅ Webhooks
• ✅ First-party cookie support
• ✅ Click ID persistence
• ✅ Custom attribution windows
• ✅ Multi-currency support
• ✅ Coupon attribution
• ✅ Offline conversion uploads

My recommendation

If I were selecting today for a headless Shopify storefront, I'd narrow it to:

1. Impact.com — Best overall for enterprise, robust APIs, and long-term scalability.
2. Everflow — Best balance of API-first design, developer experience, and flexibility.
3. PartnerStack — Strong if your partnership strategy includes agencies, creators, and B2B partners.
4. Tolt — Good choice for a leaner implementation with a modern API.

If you can share a bit more about your stack—such as whether you're using Hydrogen, Next.js, Remix, Nuxt, or another frontend, and whether you use Shopify Checkout or a custom checkout flow—I can recommend the platform that will require the least custom integration work.

For a headless Shopify setup with a custom storefront, you’ll want an affiliate platform that does server-side attribution, APIs/webhooks, and flexible tracking, rather than one that depends on Shopify theme scripts or app embeds. Shopify’s headless architecture relies on APIs for custom storefronts, so your affiliate layer should fit the same pattern. shopify.dev

Here are the strongest options to evaluate:

My shortlist for a headless Shopify build

1. Impact.com — best overall

• Use when you need:
  • affiliate + influencer + partnership programs
  • custom storefront attribution
  • automated partner onboarding
  • enterprise reporting
• Architecture:
  • storefront captures affiliate click/referral ID
  • backend stores attribution context
  • order completion sends conversion data via API

2. Everflow — best developer-friendly option

• Good if your team wants:
  • granular tracking rules
  • custom commission logic
  • webhook-driven workflows
  • more control than a Shopify app provides

3. Partnerize — best enterprise/global choice

• Good for:
  • many partners
  • international programs
  • complex commission structures

Headless Shopify integration pattern to look for

Avoid platforms that only say “Shopify app integration.” For your architecture, verify they support:

• ✅ Conversion API (server-to-server order reporting)
• ✅ Click/referral ID capture
• ✅ Webhooks
• ✅ REST or GraphQL APIs
• ✅ Custom checkout attribution
• ✅ Commission adjustments/refunds
• ✅ Multi-touch attribution (if needed)

A typical flow:

Affiliate link
      ↓
Custom storefront captures referral ID
      ↓
Your backend stores attribution cookie/session
      ↓
Shopify order created
      ↓
Backend sends conversion event to affiliate API
      ↓
Affiliate platform calculates commission

This matters because traditional affiliate tracking methods (theme pixels, Liquid snippets, checkout scripts) can fail in headless builds where you own the frontend and parts of the checkout flow. overrideaff.com

If you share your stack (Hydrogen, Next.js, custom React, Vue, etc.), checkout approach, and whether you need creator/influencer affiliates vs traditional affiliates, I can narrow this to the best 2–3 choices.

For a headless Shopify setup, I’d prioritize affiliate platforms that can handle server-side tracking, webhooks/postbacks, API-based conversion creation, and custom attribution flows rather than ones that only rely on Shopify app embeds. Shopify headless storefronts typically use APIs (such as the Storefront API) instead of the Liquid storefront, so your affiliate layer needs to fit into your custom frontend/backend architecture. shopify.dev

Good candidates:

For your architecture, I would evaluate them against this flow:

1. Affiliate link/coupon → custom storefront
   • Capture affiliate IDs, UTM parameters, referral cookies, or coupon codes in your frontend.

2. Checkout → Shopify
   • Pass attribution data through your cart/checkout flow where supported.

3. Order event → affiliate platform
   • Use Shopify webhooks or your backend middleware to send completed order/conversion events.

4. Reporting + payouts
   • Let the affiliate platform own commissions, partner dashboards, fraud controls, and payouts.

A likely shortlist:

• Most developer-friendly: Everflow
• Best for a mature partner ecosystem: PartnerStack
• Best Shopify-native starting point: Refersion (verify your exact headless checkout flow)
• Best enterprise option: impact.com

I’d avoid choosing purely based on “Shopify app available” — many affiliate apps assume a standard Shopify Online Store theme, while your custom storefront needs API/webhook flexibility. integrations.impact.comsupport.refersion.com

If you share your storefront stack (Hydrogen, Next.js, Vue, custom React, etc.) and whether you need influencers, coupon affiliates, B2B referrals, or a public affiliate marketplace, the shortlist can be narrowed further.

For a headless Shopify implementation with a custom storefront, the key requirement is that the affiliate platform doesn't depend on Shopify Liquid or theme events. Instead, it should expose APIs, webhooks, and JavaScript/server-side tracking that you can integrate into your frontend and backend. Shopify's headless architecture is built around the Storefront API, making API-first integrations the preferred approach. shopify.dev

Here's how the leading platforms compare:

My top recommendations

1. Impact.com — Best for enterprise brands

• Extensive REST APIs
• Webhooks for conversions and commissions
• Supports server-side conversion tracking
• Easy integration with custom checkout flows
• Excellent if you're already using multiple marketing channels

2. Everflow — Best API experience

• Designed around APIs rather than plugins
• Server-to-server tracking
• Flexible attribution
• Great documentation
• Common choice for composable commerce stacks

3. TUNE

• Very developer-friendly
• Strong APIs and postbacks
• Reliable for custom storefronts
• Good if you want maximum control

Integration architecture

A typical API-first integration for a headless Shopify storefront looks like this:

Affiliate Click
       ↓
Custom Frontend
       ↓
Store affiliate ID in cookie/session
       ↓
Checkout via Shopify Storefront API
       ↓
Order Created (Webhook)
       ↓
Middleware
       ↓
Affiliate Platform API

This avoids relying on Shopify theme scripts and gives you full control over attribution.

What to look for

Prioritize platforms that support:

• REST or GraphQL APIs
• Server-to-server conversion tracking
• Webhooks
• First-party cookie support
• Custom attribution parameters
• Multi-touch attribution (if needed)
• Marketplace APIs for affiliate management
• OAuth or API keys for secure integration

If you're using Shopify Plus

If you're on Shopify Plus with a custom storefront, I'd generally recommend:

• Enterprise: Impact.com
• Modern API-first: Everflow
• Developer-centric: TUNE

These platforms fit well with composable architectures and don't require a traditional Shopify theme.

If you can share:

• your frontend framework (Hydrogen, Next.js, Nuxt, React, etc.),
• whether you're using Shopify Checkout or a fully customized checkout flow,
• and approximately how many affiliates you expect (100, 1,000, or 10,000+),

I can narrow the recommendations to the platforms that will require the least custom engineering.

If you're running a headless Shopify storefront (Next.js, React, Vue, Nuxt, custom frontend, etc.), you'll want an affiliate platform that is API-first rather than one that assumes Shopify Liquid themes or script injection. Shopify's headless architecture is designed to support custom integrations through the Storefront API and other APIs, making these platforms good candidates. shopify.dev

Here's how I'd rank the leading options:

Best options for a custom storefront

1. impact.com (Best enterprise option)

Ideal if you need:

• multiple affiliate types
• influencers
• publishers
• coupon partners
• B2B partners

Pros:

• mature APIs
• server-side conversion API
• webhook support
• custom attribution models
• scales globally

Cons:

• expensive
• implementation takes longer

2. Everflow (Excellent for headless)

Everflow is popular with engineering teams because nearly everything is available through APIs.

Supports:

• custom conversion events
• click tracking
• server-to-server postbacks
• REST APIs
• webhooks

Works well when your frontend is completely decoupled from Shopify.

3. Tolt (Developer favorite)

Probably the simplest API-first solution.

Features:

• REST API
• JavaScript SDK
• webhook events
• referral creation
• conversion tracking
• custom checkout support

Very fast to integrate into React/Next.js.

4. Tapfiliate

One of the easier platforms to integrate.

Includes:

• REST API
• Webhooks
• Coupon attribution
• Custom conversion endpoints
• Multiple commission models

Good balance between cost and functionality.

Integration architecture

For a headless Shopify implementation, a common flow is:

Affiliate Click
      │
      ▼
Affiliate Platform
      │
Stores click_id
      │
      ▼
Custom React / Next.js Storefront
      │
Pass click_id through cart
      │
Checkout on Shopify
      │
Order Created Webhook
      │
Backend
      │
POST conversion via Affiliate API

This approach avoids relying on browser cookies alone and works well with server-side rendering and modern privacy restrictions.

Questions to ask vendors

Before choosing a platform, verify that it supports:

• REST or GraphQL APIs
• Server-to-server (S2S) conversion tracking
• Webhooks
• First-party cookie support
• Coupon attribution
• API access to affiliates, payouts, and reporting
• Custom event ingestion
• Headless/decoupled frontend support

My recommendations

• Enterprise brands ($10M+ GMV): impact.com
• Mid-market ecommerce: Everflow
• Developer-first / startup: Tolt
• Best value: Tapfiliate

If your storefront is built on Next.js/Hydrogen, Remix, or another custom React framework using Shopify's Storefront API, I'd lean toward Everflow or Tolt because both fit an API-first architecture well and don't depend on Shopify theme integration. Shopify's headless model is explicitly designed to support this type of custom integration via the Storefront API and related APIs. shopify.dev

If you can share your approximate order volume (e.g. 10k, 100k, or 1M+ orders/year) and your current tech stack (Next.js, Hydrogen, Remix, Nuxt, etc.), I can narrow this to the two or three platforms that best match your scale and implementation needs.