ChatGPT answers, unedited

For a custom ecommerce stack, you’ll generally want an affiliate platform with:

• API-first tracking and attribution
• Webhook/event support
• Custom conversion flows (not just Shopify/WooCommerce plugins)
• Flexible commission rules
• First-party tracking options (cookies, server-to-server, coupon codes, referral IDs)
• Ability to push your own order/customer data

Strong candidates:

My shortlist for a custom ecommerce stack

1. Everflow — best overall for flexible attribution

Good if you need:

• server-to-server conversion reporting
• multiple attribution models
• custom events
• affiliate, influencer, paid media, and partner tracking in one system

Typical flow:

1. Affiliate link → your site
2. Your backend captures affiliate parameters
3. Order completes
4. Your backend sends conversion event via API/postback
5. Everflow calculates commission

This avoids relying only on browser cookies.

2. TUNE — best if you want maximum control

Good if you’re building a more proprietary affiliate infrastructure and want:

• custom tracking logic
• partner portals
• granular commission rules
• direct API control

3. Impact.com — best for enterprise partner ecosystems

Choose this if you expect:

• large affiliate networks
• influencer partnerships
• brand collaborations
• multiple partner types

Architecture I’d recommend for a custom stack

Use the affiliate platform as the system of record, but keep attribution logic in your backend:

Affiliate click
      ↓
Your frontend
      ↓
Store referral ID / click ID
      ↓
Checkout
      ↓
Order service
      ↓
Affiliate API conversion event
      ↓
Webhook back to your system
      ↓
Commission + reporting

Important capabilities to verify before choosing:

• Server-side conversion API
• Click ID passthrough
• Multi-touch attribution support
• Coupon-code attribution
• Refund/cancellation callbacks
• Webhooks for: - conversion created
• commission approved
• commission reversed
• payout completed
• Custom commission calculations

For a custom ecommerce platform, I would usually evaluate Everflow vs TUNE first, then Impact.com if the program is enterprise-scale.

Yes. For a custom-stack ecommerce site, I’d prioritize affiliate platforms that let you own the checkout/event flow rather than requiring a Shopify/WooCommerce plugin.

My shortlist

1. Everflow — probably my first choice

Everflow

Everflow is particularly well suited to a custom stack because it's API-first and supports server-to-server postbacks rather than forcing you to depend on client-side tracking. Its documentation specifically recommends S2S postbacks where possible and supports custom events such as signup, purchase and upsell. www.everflow.io

For example, your flow could be:

Affiliate link
    ↓
Your landing page
    ↓
Store affiliate ID / click ID
    ↓
Custom checkout
    ↓
Order created
    ↓
Your backend → Everflow conversion API/postback
    ↓
Everflow attributes + calculates commission
    ↓
Webhook → your backend
    ↓
Order/commission status updated

The big advantage is that you can pass your own identifiers and revenue/event data through the system. Everflow currently supports up to 10 sub and adv parameter slots, which is useful when you want to preserve things like affiliate ID, campaign, creative, placement, customer ID, coupon, etc. helpdesk.everflow.io

I'd pick this if attribution flexibility is the primary requirement.

2. impact.com — best if you need enterprise-grade attribution

impact.com

impact.com is stronger if you're thinking beyond traditional affiliate links—cross-device journeys, multiple partner types, larger partner ecosystems, etc. Its tracking can be integrated through APIs, and its tracking system supports cross-device attribution. impact.com

It's likely more platform than you need if you're simply trying to launch an affiliate channel on a custom ecommerce site, though.

3. TUNE — strong alternative for maximum control

TUNE

TUNE is worth evaluating if you want a highly configurable affiliate infrastructure and expect the affiliate program itself to become fairly sophisticated. It's closer to an affiliate/performance-marketing infrastructure layer than a lightweight ecommerce plugin.

4. Rewardful — only if you want simplicity

Rewardful

Rewardful has REST APIs, webhooks and conversion tracking, but its sweet spot is much more straightforward affiliate programs, particularly SaaS/subscription businesses. www.everflow.ioimpact.comwww.rewardful.com

For a genuinely custom ecommerce attribution model, I'd take Everflow over it.

What I'd specifically look for in your integration

Don't just evaluate whether they have an API. Ask each vendor whether you can implement these server-side:

1. Click → affiliate ID persistence
2. Conversion API/postback from your order service
3. Pass your own order ID/customer ID
4. Pass gross sales, discounts, tax, shipping and net commissionable revenue independently
5. Support pending → approved → refunded/cancelled order states
6. Partial refunds and commission reversals
7. Coupon/code attribution
8. Multiple attribution models—first click, last click, coupon, etc.
9. Custom sub_id/metadata fields
10. Webhooks back into your system when commissions change
11. Idempotency so retrying an order event doesn't create duplicate commissions
12. Ability to reconcile the platform against your own order database

That last group is important. For a custom ecommerce stack, I'd make your database the source of truth for orders, with the affiliate platform acting as the attribution/commission engine—not the other way around.

My ranking for your stated requirement: Everflow → impact.com → TUNE → Rewardful. Everflow is the one I'd prototype first because the combination of API-first architecture, S2S postbacks, custom event tracking and flexible attribution maps particularly well to a custom ecommerce backend. www.everflow.io

If you tell me roughly your order volume, whether you need recurring commissions, and your desired attribution model (last-click vs first-click vs multi-touch/coupon), I can narrow this to 2–3 and compare their actual API/webhook architecture and pricing.

For a custom ecommerce stack, I’d prioritize platforms that support server-to-server conversion tracking, APIs, webhooks/postbacks, and configurable attribution rules rather than ones that depend heavily on a Shopify-style plugin.

My shortlist

1. Everflow — probably my first choice

Everflow

Everflow is particularly attractive if you want to own the integration. It supports first-party tracking, server-to-server postbacks, granular event tracking, and a full API for pushing/pulling data. Its current platform also emphasizes attribution across affiliates, paid media, organic traffic, and other channels. www.everflow.io

For example, your stack could do:

affiliate click → your customer/session ID → order → server-side conversion → Everflow

You can then send order value, currency, SKU/product information, customer events, renewals, upsells, etc. rather than treating "checkout completed" as the only conversion. Everflow also supports a large number of configurable sub-ID dimensions, which is useful for passing your own attribution metadata. helpdesk.everflow.io

2. impact.com — strongest if you expect a sophisticated partner program

impact.com

impact.com is a good choice if affiliates will eventually coexist with influencers, creators, referral partners, paid media, strategic partnerships, etc. It supports API-based tracking and says its ecosystem can be connected through REST/GraphQL APIs, webhooks, SFTP, or GTM. impact.com

Its cross-device and multi-touch capabilities are also worth considering if your attribution requirements go beyond simple last-click affiliate attribution. impact.com

3. TUNE — worth evaluating if your engineering team wants maximum control

TUNE is the one I'd investigate alongside Everflow if your requirements are unusually custom—e.g. your own attribution engine, unusual conversion events, multiple storefronts, or lots of server-side integration logic.

One I'd probably not lead with

PartnerStack is technically capable—the API can create customers and record transactions, and it supports server-side attribution. docs.partnerstack.com But it's particularly oriented toward B2B/SaaS partner programs. For a conventional ecommerce business with SKU/order-level affiliate attribution, Everflow or impact.com would generally be a more natural starting point.

What I'd require from whichever vendor you choose

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

• First-party click ID that you can persist in your own database
• Server-to-server conversion API/postback
• Ability to pass your own order ID, customer ID, SKU, subtotal, discount, tax, currency
• Multiple conversion events — purchase, refund, cancellation, repeat purchase, upsell
• Idempotency/deduplication
• Custom attribution windows
• Configurable first/last/multi-touch attribution
• Sub-ID/custom metadata fields
• Webhooks for affiliate/conversion events
• API access to commissions, partners, conversions and reporting
• Ability to reverse or adjust commissions after refunds/chargebacks
• A way to reconcile your order database against the affiliate platform

If you're building the integration from scratch, I'd start with Everflow vs. impact.com, with TUNE as the third option if your engineering team wants especially deep control.

If you tell me roughly your stack (e.g. Node/Rails/PHP), payment processor, order volume, and whether attribution needs to be last-click vs. multi-touch, I can narrow this down to the best 2–3 and sketch the actual API/webhook architecture.

For a custom ecommerce stack, I’d shortlist Everflow, impact.com, and TUNE. If API/webhook flexibility is the deciding factor, Everflow is probably the best fit.

1. Everflow — my first choice

Everflow is particularly well suited if you want your own backend to remain the source of truth and use the affiliate platform primarily for tracking, attribution, partner management, and payouts.

It exposes a full-access API plus webhooks and postbacks, explicitly designed for integrating with a custom tech stack and triggering real-time workflows. www.everflow.io

Its attribution layer supports things like:

• click-based attribution
• coupon-code attribution
• impression/view-through attribution
• first-touch vs. last-touch models
• conversion events beyond the initial purchase helpdesk.everflow.io

A custom implementation could look roughly like:

Affiliate click → Everflow tracking ID → your checkout → order event → Everflow conversion API → webhook → your data warehouse/commission system

That's attractive if you need to implement unusual rules such as SKU-specific commissions, subscription renewals, refunds, customer lifetime value, or custom attribution windows.

Everflow API & Webhooks documentation

2. impact.com — strongest for sophisticated enterprise attribution

I'd consider impact.com if affiliate is only one part of a broader partnership/marketing attribution system.

It supports API-based event tracking and can connect systems through REST/GraphQL APIs, webhooks, SFTP, or GTM. It also emphasizes cross-device attribution and tracking events beyond simple purchases. impact.com

It's especially compelling if you eventually want to attribute:

• affiliates
• influencers
• referrals
• paid/social channels
• subscriptions
• app events
• multiple customer touchpoints

rather than simply asking "which affiliate got this order?"

The tradeoff is that it's a considerably broader enterprise platform, so Everflow may feel cleaner if your engineering team primarily wants programmable affiliate infrastructure.

3. TUNE — good if you want network-level control

TUNE has extensive APIs for affiliates, advertisers, offers, and tracking links, plus event subscriptions/webhooks. developers.tune.com

It's a good choice if you're building something closer to an affiliate network/platform, rather than simply running an affiliate program for your ecommerce business.

Its Network API is enterprise-oriented, though, so I'd put it behind Everflow for a typical custom ecommerce implementation. developers.tune.com

What I'd choose

If your priority is "we have a custom stack and want maximum control over attribution":

1. Everflow → best overall
2. impact.com → best for enterprise/multi-channel attribution
3. TUNE → best if you're building network-like functionality

One important architectural point: don't let the affiliate platform become the canonical order database. Keep your own immutable order_id, customer_id, affiliate_id, click_id, coupon, commissionable_amount, and attribution metadata. Send conversion events server-to-server and consume webhooks back into your system.

If you tell me your stack (e.g. Node/Rails/Python), checkout flow, subscription vs. one-time purchases, and the attribution rules you need, I can compare Everflow vs. impact.com at the API/event-schema level and show what the integration would actually look like.

For a custom ecommerce stack, I’d prioritize platforms that support server-to-server conversion tracking, APIs, webhooks/postbacks, and configurable attribution rather than ones that depend heavily on a Shopify/WooCommerce plugin.

My shortlist

1. Everflow — my first choice for a custom stack

Everflow is particularly attractive if your engineering team wants to own the integration. Its platform is API-first, supports S2S postbacks, webhooks and APIs, and lets you define conversion events such as purchases and upsells. It also supports granular placement/sub-ID data, which is useful if you want attribution beyond simply “affiliate X generated order Y.” www.everflow.io

For example, your flow could be:

affiliate click → your site → persist click/sub IDs → checkout → order event → Everflow S2S conversion → commission

That architecture keeps your order system as the source of truth rather than relying on a browser pixel.

Everflow developer/platform information

2. impact.com — strongest if you're building a broader partnership program

impact.com is a good choice if affiliates are only one piece of the strategy and you also want influencers, creators, referral partners, etc. It supports REST/GraphQL APIs and webhooks, and its attribution tooling can deduplicate across affiliate, influencer, paid search, social and other channels. get.impact.com

I'd lean toward it over Everflow if you need a full partner-management ecosystem, rather than primarily sophisticated tracking infrastructure.

impact.com platform

3. PartnerStack — good, but more SaaS-oriented

PartnerStack has a solid API/S2S model and webhooks, including customer and transaction events. Its model is especially convenient when attribution follows a referred customer through subsequent purchases/subscriptions. docs.partnerstack.com

For a conventional ecommerce store with complicated order-level attribution, though, I'd generally put Everflow or impact.com ahead of it.

PartnerStack developer docs

What I'd choose

If your requirements are specifically “custom ecommerce + API/webhooks + maximum control over attribution”, I'd start with Everflow.

The key questions I'd use in the technical evaluation are:

• Can we send conversions server-to-server with our own order/customer IDs?
• Can we pass arbitrary sub IDs / click IDs / campaign IDs?
• Can we fire different events for purchase, refund, cancel, repeat_purchase, upsell, etc.?
• Can we reverse or modify commissions when an order is refunded?
• Can we implement our desired last-click / first-click / custom attribution rules?
• Can we reconcile the platform's conversions against our internal order database?
• Can we export raw attribution data to our warehouse?
• Can we avoid making the affiliate platform the authoritative source for order state?

Everflow explicitly recommends S2S postbacks for accuracy/resilience and supports flexible conversion events, which maps very well to that architecture. www.everflow.iowww.everflow.io

If you tell me your checkout flow (e.g. React/Next.js, custom backend, Stripe/Adyen/etc.), whether purchases are one-time vs. subscription, and the attribution rules you want, I can narrow this to 2–3 options and sketch the API/webhook architecture for each.

For a custom-stack ecommerce site, I’d shortlist Everflow, impact.com, and TUNE. The key distinction is how much control you want over the tracking/attribution layer versus how much of the partner-management ecosystem you want out of the box.

1. Everflow — my first choice

This is probably the strongest fit if your engineering team wants to own the integration.

Everflow exposes a full-access API plus webhooks and postbacks, specifically intended for integrating into custom tech stacks and triggering real-time workflows. www.everflow.iodevelopers.tune.com

For your checkout, you can use server-to-server conversion tracking rather than relying exclusively on browser cookies. Everflow supports S2S postbacks, JavaScript SDK and HTML pixels. helpdesk.everflow.io

The particularly useful part is its attribution configuration: it can prioritize coupon codes, transaction IDs, cookies, fingerprinting, email, and clickless attribution, so you aren't locked into simple last-click tracking. helpdesk.everflow.io

It also supports event-based attribution beyond the initial sale—engagement, conversion, renewal, etc.—which is useful if your economics involve repeat purchases or subscriptions. www.everflow.io

I'd pick Everflow if your architecture looks something like:

Affiliate click → your backend → customer/order ID → attribution service → order event → Everflow → webhook → your data warehouse/CRM

That gives you a lot of freedom to maintain your own customer/order model.

2. impact.com — best if you want the broader ecosystem

impact.com is also very strong technically. It supports REST/GraphQL APIs, webhooks and SFTP, and says that anything beyond its 150+ prebuilt integrations can be wired into your stack through those interfaces. get.impact.com

Its strength is less "give my engineers a blank canvas" and more affiliate + influencer + partnership management + attribution in one system. It supports multi-touch attribution and deduplication across affiliate, influencer, paid search, social and direct channels. get.impact.com

I'd lean toward impact.com if you expect to eventually have:

• affiliates
• influencers/creators
• coupon partners
• referral partners
• paid media
• cross-channel attribution
• complex partner contracts/payout rules

It's a more comprehensive partnership platform.

3. TUNE — best for maximum network customization

TUNE has substantial APIs: its Network API lets enterprise customers programmatically manage network functionality, while its JavaScript SDK can generate tracking sessions and track clicks. developers.tune.com

It can also generate tracking links programmatically with arbitrary parameters, which is useful if your affiliate links need to carry your own IDs or metadata. developers.tune.com

I'd consider TUNE particularly if you're effectively building your own affiliate network infrastructure, rather than simply running an affiliate program for your store.

What I'd choose for your situation

If your priority is specifically:

"We have our own ecommerce stack and want flexible attribution that we can integrate deeply through APIs/webhooks."

I'd rank them:

1. Everflow → best technical fit
2. impact.com → best if partnership ecosystem matters
3. TUNE → best if you're building something highly network/customization oriented

The important thing is to avoid designing your integration around a browser pixel. For a custom stack, I'd make your order backend the source of truth and send a conversion event/postback containing something like:

affiliate_id + click_id + order_id + customer_id + order_value + currency + SKU/items + coupon + timestamp

Then let the affiliate platform resolve attribution while your own data warehouse retains the raw event trail. That makes changing attribution rules or even switching affiliate platforms substantially easier.

If you tell me your stack (e.g. Next.js + Node, Rails, Laravel, Python, headless Shopify, custom checkout, etc.) and whether you need first/last/multi-touch, coupon attribution, recurring commissions, or cross-device tracking, I can narrow this down to the best 1–2 and sketch the API/webhook architecture.

For a custom ecommerce stack, I’d prioritize affiliate platforms that support server-to-server tracking + APIs + webhooks, rather than ones that assume Shopify/WooCommerce.

My shortlist

1. Everflow — my first choice for your situation.
Its positioning is explicitly around a full-access API, postbacks, and webhooks, with the ability to build custom integrations and real-time workflows. www.everflow.io

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

Affiliate click → your site → your attribution layer → checkout → order event → Everflow → commission

You can keep your own customer/order IDs and attribution logic rather than forcing the ecommerce platform to conform to the affiliate vendor.

Everflow API & Webhooks

2. impact.com — best if you expect the program to become sophisticated.
It supports REST/GraphQL APIs and webhooks and specifically advertises integration with custom stacks. It also has broader partnership functionality beyond conventional affiliates—creators, influencers, paid channels, etc. get.impact.com

impact.com Developer/API platform

3. TUNE — excellent if you want infrastructure-level control.
TUNE exposes Network, Advertiser, and Affiliate APIs and has a JavaScript SDK for generating tracking sessions and sending clicks. developers.tune.com

TUNE Developer Hub

4. PartnerStack — very good, but I'd lean toward it for partner/referral programs rather than pure ecommerce affiliates.
It has REST APIs and configurable webhooks, including transaction events. Its architecture lets you create customers with your own unique customer key and then attribute subsequent purchases to the referring partner. docs.partnerstack.com

PartnerStack API & Webhooks docs

5. FirstPromoter — worth considering if you want something lighter.
It supports webhooks for events such as promoter signup, referral conversion, and commission approval, which can work nicely with a custom backend. help.firstpromoter.com

What I'd choose

If your key requirement is "we own the ecommerce stack and want the affiliate platform to plug into our attribution engine", I'd rank them:

Everflow > TUNE > impact.com > PartnerStack > FirstPromoter

If you're doing millions of orders / sophisticated attribution, I'd spend the most time evaluating Everflow vs. impact.com vs. TUNE.

One architectural point I'd strongly recommend: don't make the affiliate platform your source of truth for attribution. Generate/persist your own click_id / affiliate_id / campaign_id against the shopper or session, then send the eventual order/conversion to the affiliate system via API/postback. That gives you freedom to change affiliate vendors later and lets you implement rules like last affiliate click, first touch, coupon attribution, assisted conversion, hold periods, refunds, partial cancellations, and multi-touch attribution yourself.

If you tell me your stack (e.g. Next.js + Node, Laravel, Rails, Python, custom checkout, Stripe/Adyen/etc.) and roughly monthly orders/GMV, I can narrow this to 2–3 options and compare the actual integration architecture/API calls.

For a custom ecommerce stack, I’d prioritize platforms that support server-to-server tracking + APIs + webhooks, rather than ones that depend heavily on a Shopify/WooCommerce plugin.

My shortlist

1. Everflow — my pick if attribution flexibility is the priority.

Everflow exposes a full-access API plus postbacks and webhooks, explicitly positioning them for custom integrations and real-time workflows. www.everflow.io

This is particularly attractive if you want your own backend to determine things like:

• affiliate/referral ID
• click/session ID
• first-touch vs. last-touch
• coupon attribution
• new vs. returning customer
• SKU/product-level commissions
• refunds/cancellations
• custom commission rules
• server-side conversion events

In other words, you can make your ecommerce backend the source of truth and use the affiliate platform primarily for tracking, partner management, commission calculation, and reporting.

Everflow

2. Refersion — probably the easiest ecommerce-oriented option.

Refersion specifically supports custom stores through its API, and its conversion webhooks include order, affiliate, offer and click information. www.refersion.dev

Its newer webhook system is particularly useful for a custom stack: conversion creation/approval/denial, payouts, affiliate changes, promotion methods, and other events can be pushed to your infrastructure, with signed payloads and replay/retry capabilities. www.refersion.com

It also supports SKU-level tracking and different commissions for products, new vs. returning customers, and subscriptions. www.refersion.com

Refersion

3. PartnerStack — excellent API, but I'd only choose it if your model is more "partner program" than traditional ecommerce affiliate.

PartnerStack's REST API exposes customers, transactions, deals, leads, partnerships and webhooks. Its Transactions API lets your backend explicitly send transaction amounts, products, categories and unique transaction IDs, with the transaction automatically attributed to the referring partner. docs.partnerstack.com

That's a very nice architecture for a custom backend, but PartnerStack tends to make more sense for SaaS/B2B referral and partner ecosystems than a conventional DTC affiliate program.

PartnerStack

What I'd choose

If you told me "we don't want to bend our architecture around the affiliate vendor; we want to own attribution and integrate through APIs/events", I'd test Everflow first, then Refersion.

A good architecture would look like:

Affiliate click → your site → your own customer/session ID → checkout → ecommerce backend → affiliate conversion API/postback → webhook back into your event pipeline

That gives you considerably more control than putting affiliate JavaScript directly into checkout and letting the vendor determine everything.

If you tell me your stack (e.g. Next.js + Node, Laravel, Rails, custom Go, headless Shopify, Stripe, etc.) and whether you need first-touch, last-touch, multi-touch, coupon-based, or lifetime attribution, I can narrow this down to 2–3 platforms and compare their actual integration flows/API capabilities.

For a custom e-commerce stack, I’d prioritize platforms where your backend can own the attribution logic rather than relying on a Shopify/WooCommerce plugin.

My shortlist

1. Everflow — my first choice.
Its full-access API, webhooks and server-to-server postbacks are specifically designed for custom integrations. You can send conversions/events from your backend rather than depending on browser pixels, and it supports custom parameters for passing attribution context. www.everflow.io

That makes a flow like this straightforward:

affiliate link → your site → capture click/affiliate ID → persist attribution → checkout → your backend → Everflow S2S conversion

You can also pass things like order ID, revenue, product/category, affiliate/sub IDs, and fire subsequent events such as refunds or upsells. Everflow explicitly recommends S2S tracking where possible. helpdesk.everflow.io

Everflow API & Webhooks

2. impact.com — strongest if you're building a sophisticated partnership operation.
impact.com offers API-based conversion tracking, cross-device attribution, and can integrate via REST/GraphQL APIs and webhooks. It also has a large set of prebuilt e-commerce integrations if you eventually need them. impact.com

I'd lean toward it if you expect affiliates + creators + influencers + referral partners + more complex customer journeys rather than just a conventional affiliate program.

impact.com partnership tracking

3. PartnerStack — very easy API integration, but I'd rank it lower for pure e-commerce.
PartnerStack has a REST API and lets you submit transactions from your backend, with the transaction automatically attributed to the partner associated with the customer. docs.partnerstack.com It also has first-party link tracking through PartnerStackJS. docs.partnerstack.com

The caveat is that its model is particularly well suited to SaaS/customer-account/recurring-revenue programs. For a highly customized retail attribution model, Everflow or impact.com gives you more freedom.

What I'd choose

If your requirement is specifically:

"We have our own checkout/order system and want maximum control over attribution."

I'd start with Everflow.

The important technical requirement isn't just "has an API." I'd verify that the vendor supports:

• S2S conversion tracking
• Persistent affiliate/click IDs
• Custom parameters/sub-IDs
• Multiple conversion events
• Refund/chargeback reversal
• Partial refunds
• Dynamic commission calculations
• Attribution windows you can control
• First-party tracking
• Webhooks for downstream events
• API access to raw-ish conversion/partner data
• Idempotency/deduplication
• Ability to attribute repeat purchases to the original referral
• Flexible payout rules by product/category/order value

For a custom stack, I'd also avoid making the affiliate vendor your source of truth for orders. Keep the canonical order and attribution records in your own database, then send the appropriate conversion/event signals to the affiliate platform. That gives you much more freedom to change vendors later.

If you tell me your stack (e.g. Node/Go/Rails, payment processor, whether customers have accounts, and whether attribution needs first-click/last-click/multi-touch), I can narrow this to the best 2–3 and outline exactly how I'd integrate each one.

For a custom ecommerce stack where API/webhook flexibility and attribution control matter, I’d shortlist these:

My pick: Everflow

Everflow is probably the strongest fit if your engineering team wants the affiliate platform to behave like an attribution service rather than a plug-in.

It provides a full-access API, postbacks, and webhooks specifically for connecting into custom tech stacks. www.everflow.io It also supports multiple attribution mechanisms, including click/transaction-ID attribution and coupon-code attribution, with configurable attribution priority. helpdesk.everflow.io

Everflow developer/API capabilities

A typical architecture would be:

affiliate click → your site → persistent attribution ID → checkout/order → server-side conversion → Everflow API/postback → webhook → your warehouse/CRM

That gives you considerably more control than relying on a JavaScript-only affiliate integration.

Best if you want easier ecommerce integration: Refersion

Refersion is attractive if you want less engineering work while retaining a custom integration path. Refersion explicitly supports custom API integrations and server-side order tracking for stores that aren't on its native ecommerce integrations. www.refersion.com

Its current webhook system can push conversion, approval/denial, payment, affiliate, and other events to your endpoints, with signed HMAC-SHA256 payloads and replay protection. www.refersion.com

Refersion API and integrations

Refersion also has first-party tracking and supports things like SKU-level commissions, coupon attribution, new-vs-returning-customer rules, and subscription commissions. support.refersion.com

TUNE if attribution/business rules are extremely custom

TUNE is worth considering if you're building a fairly sophisticated affiliate/network operation. Its developer platform exposes APIs and event subscriptions, so it can be deeply embedded into your own infrastructure. developers.tune.com

TUNE developer documentation

How I'd choose

• Engineering control is #1: Everflow
• Ecommerce + easy implementation: Refersion
• Enterprise-grade custom affiliate/network logic: TUNE
• Primarily SaaS/referral partnerships: PartnerStack

One important distinction: if by “flexible attribution” you mean you want to define exactly how credit is assigned—e.g. last-click vs first-click, coupon override, new-customer-only, multi-touch, cross-device, recurring revenue, custom commission rules—I would put Everflow clearly ahead of Refersion.

If you tell me your stack (e.g. Next.js + Node, Rails, Laravel, custom checkout, Stripe, etc.) and the attribution rules you need, I can map out the lowest-engineering integration architecture and compare the actual APIs/webhooks of 2–3 vendors.

Yes. For a custom ecommerce stack, I’d prioritize platforms that let your backend be the source of truth for conversions rather than forcing you into a Shopify/WooCommerce plugin.

My shortlist

1. Everflow — my pick for maximum flexibility

Everflow is probably the strongest fit if your custom stack has nonstandard checkout, multiple domains, unusual commission rules, or sophisticated attribution requirements.

Its platform exposes a full-access API plus webhooks and postbacks, explicitly designed for integrating with custom tech stacks and real-time workflows. www.everflow.io

The architecture I'd use is:

Affiliate click → your site → your own session/customer ID → checkout → backend order event → Everflow conversion API/postback → webhook back to your systems

That lets you retain your own order/customer IDs and attribution logic rather than making the affiliate platform the canonical commerce database.

Best choice if: engineering flexibility matters more than absolute simplicity.

2. Tapfiliate — probably the easiest custom-stack option

Tapfiliate is particularly interesting if you want API-first integration without the heavier enterprise machinery of Everflow.

Their REST API supports programmatic affiliate management and server-side conversion tracking, and they specifically position it for proprietary/custom engines. They also support real-time webhooks for conversions, payouts and partner signups. tapfiliate.com

This gives you a fairly clean integration:

affiliate link
     ↓
your frontend
     ↓
affiliate/click ID stored in your session
     ↓
your checkout
     ↓
order.created
     ↓
Tapfiliate conversion API
     ↓
conversion webhook → your backend

Best choice if: you want developers to be able to integrate it quickly without adopting a huge affiliate infrastructure platform.

3. Refersion — strongest ecommerce-oriented choice

Refersion is worth considering if you're primarily a DTC/ecommerce business.

It now supports first-party attribution, including referral links, coupon codes and email attribution, and its attribution model associates the click/session with a unique cart ID and subsequently matches that to the order. www.refersion.com

Importantly for a custom stack, Refersion supports merchant webhooks for new/approved/denied conversions, payments, affiliates and affiliate changes, with JSON payloads and webhook signatures. www.refersion.dev

Their custom integration documentation also specifically describes sending order information from your server and matching the same cart_id between the click and order. support.refersion.com

Best choice if: you're a conventional ecommerce brand and want less engineering overhead than Everflow.

4. PartnerStack — good, but I'd choose it for a different reason

PartnerStack has a strong API/webhook architecture. Its API can handle customer conversion and attribution, while webhooks cover customer, transaction, lead and partnership events. tapfiliate.comdocs.partnerstack.com

However, it's more compelling when you're building a partner ecosystem—SaaS referrals, resellers, B2B partners, etc.—rather than a straightforward ecommerce affiliate program.

So I wouldn't make it my first choice for a typical DTC store.

What I'd choose

If I were evaluating this for your architecture:

Everflow → if you want the most control over attribution and expect complexity.

Tapfiliate → if you want the best balance of custom API integration + relatively easy implementation.

Refersion → if you're primarily ecommerce/DTC and want the least amount of custom affiliate plumbing.

One important distinction: "has an API" isn't enough. For a custom stack, I'd specifically test whether the platform lets you control these pieces:

1. Click ID generation/persistence
2. First-party/session-based tracking
3. Server-to-server conversion reporting
4. Your own order_id / customer_id
5. Coupon-code attribution
6. Multiple attribution models
7. Conversion reversal/refunds
8. Partial refunds
9. Commission overrides
10. Custom metadata/sub IDs
11. Webhook signatures + retries
12. Idempotent conversion handling
13. Cross-domain checkout
14. Subscription/LTV commissions, if relevant

For your use case, I'd start demos with Everflow and Tapfiliate, then use Refersion as the ecommerce-oriented benchmark. Everflow has the highest ceiling; Tapfiliate is likely to have the lowest engineering friction.

If you tell me your stack (e.g. Next.js/Node, Rails, Laravel, etc.), checkout/payment provider, and whether attribution needs to be last-click, first-click, coupon-based, or multi-touch, I can narrow this to the best 1–2 and sketch the exact API/webhook architecture.

For a custom-stack ecommerce site, I’d shortlist these:

My pick: Everflow

For your specific requirements, Everflow is probably the easiest fit. It is API-first and explicitly supports pushing/pulling data through its API, while its tracking supports first-party/direct linking, coupon-code attribution, unlimited event tracking, and granular sub-IDs. www.everflow.io

That makes it a good architecture for something like:

affiliate click → your site → your own customer/order system → conversion event → Everflow → affiliate commission

You can keep your order/customer database as the source of truth and send Everflow the events you actually want to commission—purchase, refund, subscription renewal, upsell, etc.—rather than trying to bend your ecommerce stack around an affiliate plugin. Everflow also documents postback configurations and parameter mappings for integrating with other tracking platforms. helpdesk.everflow.io

impact.com

I'd choose impact.com if you expect the program to expand beyond conventional affiliates into creators, influencers, referrals, B2B partnerships, or other channels. It supports REST/GraphQL APIs and webhooks, and advertises 150+ prebuilt connectors. It also has fairly sophisticated cross-channel attribution and deduplication. get.impact.com

The tradeoff is that it can be a heavier platform than you need if your primary requirement is simply "give our custom backend flexible affiliate tracking."

PartnerStack

PartnerStack has a solid REST API and event-based integration model, including sending customer and payment events from your backend. docs.partnerstack.com I'd put it behind the other two for a general ecommerce use case; it's particularly compelling when the business model is SaaS/referrals rather than physical-product ecommerce.

Bottom line:
Custom ecommerce + API/webhooks + maximum attribution control → Everflow.
Ecommerce + affiliates + creators/influencers + broader partnership ecosystem → impact.com.

If you tell me whether you need last-click vs multi-touch attribution, coupon attribution, recurring commissions, refunds/chargebacks, and server-side conversion tracking, I can narrow this to the best architecture and integration approach.

Yes. For a custom-stack ecommerce site, I’d prioritize platforms that let you control the tracking/conversion layer rather than ones that assume Shopify/WooCommerce.

My shortlist

Everflow would be my first choice if your engineering team wants to own the attribution logic. Its API and webhook infrastructure is explicitly designed around affiliates, conversions, offers, partners, etc.; its conversion/event webhooks can feed your own backend, and the docs specifically account for duplicate webhook delivery and asynchronous processing. developers.everflow.io

Why I'd lean Everflow for a custom stack

You can structure the integration roughly like:

Affiliate link
      ↓
Your website
      ↓
Affiliate click ID / sub IDs
      ↓
Your checkout + order system
      ↓
Your attribution service
      ↓
Everflow conversion API
      ↓
Affiliate commission
      ↓
Webhook → your backend / BI / CRM

That gives you much more control than embedding your business logic inside an ecommerce plugin.

For example, you could retain your own:

• affiliate_id
• click_id
• customer_id
• order_id
• campaign_id
• sub1–sub5 / custom dimensions
• first-touch vs. last-touch attribution
• coupon attribution
• new-vs-existing-customer rules
• returns/refunds
• commission exclusions
• multi-touch attribution

Then send the final attributed conversion to the affiliate platform.

One important distinction

If by "flexible attribution" you mean something like:

"Affiliate A introduced the customer, Affiliate B assisted them later, but Affiliate C gets the commission if they used their coupon"

I'd choose Everflow or impact.com, rather than a lightweight affiliate SaaS. Everflow in particular is built much more like an attribution/tracking infrastructure layer than simply an affiliate dashboard. A current 2026 comparison also describes Everflow as particularly strong for server-to-server tracking and granular placement-level data. www.rewardful.com

If instead you mean:

"We just need affiliate links → orders → commissions, with a clean API and minimal engineering"

then Tapfiliate is probably the easier middle ground.

If you tell me your stack (e.g. Next.js + Node, Rails, Laravel, etc.), order volume, and whether attribution needs to be first-touch/last-touch/multi-touch, I can narrow this to 2–3 options and sketch the API/webhook architecture.

For a custom-stack ecommerce site, I’d prioritize affiliate platforms that let you own the checkout/conversion event and send attribution server-side rather than forcing a native Shopify/WooCommerce integration.

My shortlist

1. Rewardful — easiest developer experience

Rewardful explicitly supports custom checkout implementations and provides JavaScript/API-based conversion tracking. It also supports webhooks for events such as referred customers, conversions and commissions. help.rewardful.com

The attractive architecture for your stack is:

affiliate link → your site → persist affiliate ID → checkout → your backend → Rewardful conversion API → webhook → your systems

It also supports direct-page attribution, which is useful if you want custom landing pages or nonstandard referral URLs. help.rewardful.com

Rewardful developer documentation

2. PartnerStack — best if partners are a major channel

PartnerStack has both a REST API and server-to-server tracking, and its documentation specifically describes sending customer/signup and transaction events from your own application. Its webhooks can push partner events back to your infrastructure. docs.partnerstack.com

That makes it particularly interesting if your attribution model goes beyond simple last affiliate click → sale, e.g. partner → lead → customer → transaction → recurring/adjusted commission.

PartnerStack developer docs

3. impact.com — strongest for sophisticated ecommerce

I'd look at impact.com if you're expecting a substantial affiliate/influencer/creator program and need more enterprise-grade attribution, tracking, partner management, and reporting. The tradeoff is that it's generally a heavier implementation than Rewardful.

What I'd choose

For a custom ecommerce stack, my default order would be:

Rewardful → impact.com → PartnerStack

But there's an important distinction:

• Want the quickest API/webhook integration: Rewardful
• Want maximum attribution/program sophistication: impact.com
• Want a large B2B/partner ecosystem: PartnerStack
• Want relatively straightforward general affiliate management: Tapfiliate

The key question isn't just whether they have an API. I'd specifically verify that the platform supports your desired attribution model: first/last click, coupon/code attribution, cross-device behavior, attribution windows, returning customers, refunds/chargebacks, and whether your backend can be the source of truth for conversions.

If you tell me how your checkout/payment stack works (Stripe, Adyen, custom payment processor, etc.) and whether you need first-click vs last-click/multi-touch attribution, I can narrow this to 2–3 options and map the actual integration architecture.

Yes. For a custom ecommerce stack, I’d prioritize affiliate platforms that are API-first and let your backend remain the source of truth for orders/conversions.

My shortlist

1. Everflow — my first choice

Everflow is particularly well suited to a custom stack. Its platform is API-first, with a full-access API, postbacks, and webhooks for pushing/pulling marketing data and building custom workflows. www.everflow.io

It also supports granular event tracking, first-party tracking, sub-IDs, and attribution across engagement, conversion, and renewal events. www.everflow.iowww.everflow.io

For your architecture, I'd envision:

Affiliate click
      ↓
Everflow tracking
      ↓
Your ecommerce site
      ↓
Your order DB / event bus
      ↓
Conversion API/postback → Everflow
      ↓
Everflow attribution + commission
      ↓
Webhook → your systems

That gives you considerable freedom to determine when an order becomes a conversion, what revenue is commissionable, how refunds/cancellations are handled, and which metadata gets passed through.

Everflow also supports a large number of custom sub-ID dimensions, which is useful if you want to preserve your own campaign/placement/customer identifiers. helpdesk.everflow.io

Everflow developer/API capabilities

2. TUNE — worth considering if you want maximum control

TUNE is another strong choice when the affiliate system needs to behave more like infrastructure inside your own application rather than a turnkey ecommerce plugin. I'd put it near the top if your team wants deep control over tracking, offers, payouts, and partner data.

3. impact.com — strongest if partnerships extend beyond affiliates

impact.com makes more sense if you're building a broader partnerships program—affiliates plus creators, referral partners, strategic partnerships, etc. It can be powerful, but I'd generally choose Everflow first if API/webhook flexibility is the primary criterion.

4. PartnerStack — excellent API, but probably not my first ecommerce choice

PartnerStack has a REST API and webhooks, and its Transactions API lets your backend explicitly submit transaction amount, currency, product/category identifiers, and transaction IDs. docs.partnerstack.com

That's quite attractive technically. However, its model is particularly oriented toward partner/referral programs and SaaS-style customer relationships, so I'd lean Everflow/TUNE for a conventional ecommerce business with sophisticated affiliate attribution.

What I'd evaluate before signing

For a custom stack, don't just ask whether they have an API. Ask specifically whether you can:

• Create/resolve attribution server-side rather than relying entirely on browser cookies.
• Pass your own click ID / customer ID / order ID / campaign ID / sub-IDs.
• Fire conversions server-to-server.
• Handle partial refunds, full refunds, cancellations and chargebacks.
• Modify or reverse a conversion after initial submission.
• Define commissionable revenue independently of gross order value.
• Attribute repeat purchases to the original affiliate when appropriate.
• Choose or configure first-touch vs last-touch attribution.
• Receive real-time webhooks for conversion/status changes.
• Reconcile webhook events against API data.
• Export sufficiently granular raw data to your warehouse.
• Make attribution decisions in your own event pipeline, rather than being locked into the platform's JavaScript implementation.

For example, I'd strongly prefer an architecture where your checkout emits something like:

{
  "order_id": "ORD-12345",
  "customer_id": "CUS-987",
  "affiliate_click_id": "ef_abc123",
  "subtotal": 149.00,
  "discount": 20.00,
  "shipping": 8.00,
  "tax": 12.00,
  "commissionable_revenue": 129.00,
  "currency": "USD"
}

and your backend decides what gets sent to the affiliate platform. That gives you much more control than making the affiliate vendor's frontend script responsible for determining the conversion.

Bottom line: if your main requirement is “we have our own ecommerce infrastructure and want the affiliate platform to plug into our event/API architecture rather than dictate it,” I'd start with Everflow, then evaluate TUNE and impact.com against it. Everflow's combination of full API access, postbacks/webhooks, granular tracking, and custom integrations is unusually aligned with that requirement. www.everflow.iowww.everflow.io

If you tell me your stack (e.g. Node/Go/Rails + Stripe/Adyen + warehouse + event bus) and the attribution model you want, I can also lay out a concrete Everflow vs TUNE vs impact.com integration architecture and identify the likely implementation effort.

For a custom-stack ecommerce site, I’d prioritize affiliate platforms with a strong REST API + outbound webhooks + flexible conversion/commission rules, rather than platforms that expect you to install a proprietary ecommerce plugin.

Good candidates include:

• Rewardful — very developer-friendly, particularly if your checkout/payment flow can expose the right customer and transaction events. Good for straightforward affiliate/referral programs.
• Tolt — API/webhook-oriented and relatively lightweight; useful if you want to own more of the customer/checkout experience.
• PartnerStack — stronger for B2B/SaaS-style partner programs and complex partner structures.
• impact.com — much more extensive; good when you need sophisticated attribution, tracking, partner types, and enterprise workflows.
• Everflow — particularly interesting if attribution flexibility is the priority. Its tracking/postback architecture is designed for custom integrations and more complex performance marketing.
• FirstPromoter — relatively simple implementation and API capabilities, though I'd evaluate it against your exact ecommerce event model.

My shortlist

If you tell me how your checkout works (e.g. Stripe, custom payment processor, Shopify headless, etc.) and what attribution you need—last-click, first-click, coupon-based, recurring commissions, multi-touch, cross-device, refunds/cancellations—I can narrow this to the best 2–3 and compare their actual API/webhook architectures.

For a custom ecommerce stack where you want API-first integration, webhook support, and flexible attribution rules, these affiliate platforms are among the strongest options:

My top recommendations

1. Trackdesk

• Modern REST API
• Webhooks for clicks, conversions, approvals, payouts
• Supports server-to-server tracking
• Flexible attribution windows
• Easy to integrate with custom carts
• Good pricing compared to enterprise solutions

Good if you're building your own checkout and order flow.

2. Everflow
If you expect to scale significantly.

Features include:

• Multi-touch attribution
• API-first architecture
• Real-time postbacks
• Webhooks
• Fraud detection
• Custom events
• Multiple commission structures

Often chosen by larger ecommerce brands.

3. Post Affiliate Pro
One of the most customizable platforms.

Supports:

• Complete REST API
• JavaScript tracking
• Server-side conversion tracking
• Coupon attribution
• Lifetime commissions
• Custom commission logic

Works well with completely custom ecommerce systems.

Typical integration architecture

A flexible implementation usually looks like this:

1. Affiliate click lands on your site.
2. Your backend stores the affiliate ID (or click ID).
3. Customer shops normally.
4. Order is completed.
5. Your backend calls the affiliate platform's API:
   • order ID
   • customer ID
   • amount
   • products
   • affiliate/click ID
6. Affiliate platform attributes the sale.
7. Webhooks notify your backend when:
   • commission is approved
   • commission is rejected
   • payout occurs
   • affiliate details change

This keeps your ecommerce platform as the source of truth while the affiliate software manages attribution, commissions, and payouts.

Features to prioritize

For a custom stack, look for:

• REST API for all major operations
• Outbound webhooks
• Server-to-server (S2S) conversion tracking
• First-party cookie support
• Coupon-code attribution
• Multi-currency support
• Custom commission rules
• Order updates/refunds via API
• Lifetime customer attribution
• Batch import/export APIs
• OAuth or API key authentication
• Detailed reporting APIs

If your goal is maximum flexibility with minimal vendor lock-in, Trackdesk, Everflow, and Post Affiliate Pro are particularly strong choices because they expose most functionality through APIs and webhooks rather than relying on platform-specific plugins.

If you're on a custom ecommerce stack and want API- and webhook-first affiliate software, you have considerably more flexibility than if you needed a plug-and-play Shopify or WooCommerce app.

Here are some of the strongest options:

Best choices for a custom ecommerce platform

1. Everflow

Probably the most flexible if attribution is important.

Pros:

• REST API
• Rich webhook support
• Server-to-server conversion tracking
• Coupon attribution
• Multi-touch attribution options
• Custom commission rules
• Excellent reporting

Good if you're processing thousands of orders/month.

2. Post Affiliate Pro

One of the easiest to integrate into a custom backend.

Features:

• API for affiliates, commissions, referrals
• Webhooks
• Pixel or server-side tracking
• Lifetime commissions
• Custom attribution logic
• Self-hosted option available

Very flexible.

3. Tapfiliate

Developer-friendly and straightforward.

Supports:

• REST API
• Webhooks
• JavaScript tracking
• Server-side conversions
• Coupon tracking
• Custom integrations

Works well for custom ecommerce sites.

4. FirstPromoter

Excellent if you want to send conversions via API rather than relying on browser tracking.

Supports:

• API-created conversions
• Webhooks
• Custom customer IDs
• Stripe integration (optional)
• Flexible attribution

5. Tolt

A newer platform with a clean API.

Good for:

• API-first implementations
• Custom checkout flows
• Modern UI
• Easy affiliate management

Typical integration architecture

A common pattern for a custom stack is:

1. Visitor clicks affiliate link.
2. Affiliate platform issues a click ID or stores an affiliate identifier.
3. Your frontend stores the identifier (cookie or local storage).
4. Customer completes checkout.
5. Your backend sends a server-to-server conversion via the affiliate platform's API, including:
   • Order ID
   • Customer ID
   • Order value
   • Affiliate/click identifier
   • Currency
   • Products purchased
6. Webhooks notify your backend when:
   • An affiliate is approved
   • A payout is made
   • A commission is reversed
   • An order is refunded
   • Commission status changes

This approach minimizes reliance on client-side tracking and is generally more reliable than browser pixels alone.

If flexible attribution is your priority

I'd rank them as:

1. Everflow (most flexible)
2. impact.com (enterprise-grade)
3. Post Affiliate Pro (highly customizable)
4. Tapfiliate (good balance of simplicity and features)
5. Tolt (modern and developer-friendly)

If your stack already exposes order events via webhooks and you can make outbound API calls, any of these can support reliable server-side attribution. The best fit will depend on your expected affiliate volume, budget, and whether you need advanced features such as multi-touch attribution, coupon attribution, or cross-device tracking.

For a custom ecommerce stack, the most flexible affiliate platforms are generally those that expose well-documented REST APIs, outbound webhooks, server-to-server (postback) tracking, and support custom attribution logic rather than assuming Shopify/WooCommerce.

Some of the strongest options are:

If developer flexibility is your priority

I'd narrow it to:

1. Everflow – Probably the best combination of:
   • REST API
   • Real-time webhooks
   • Server-side conversion tracking
   • Multiple attribution models
   • Custom conversion events
   • Fraud prevention
   • Easy integration into a bespoke backend

2. Tapfiliate
   • Clean API
   • Simple webhook system
   • Easy to embed into a custom checkout
   • Lower cost than enterprise platforms

3. TUNE
   • Extremely customizable
   • Almost every object is API accessible
   • Built for custom integrations
   • Better suited if you're processing very high affiliate volumes.

Features to look for

For a custom ecommerce platform, you'll ideally want:

• REST API for affiliate management
• Outbound webhooks (signup, click, conversion, payout)
• Server-to-server conversion tracking
• First-party cookie support
• Coupon attribution
• Multi-touch attribution (if needed)
• Cross-device tracking
• Custom commission rules
• Refund/cancellation webhooks
• Bulk import/export APIs
• OAuth or API keys with scoped permissions

Typical integration architecture

Affiliate Link
      │
      ▼
Visitor arrives
      │
Affiliate platform records click
      │
      ▼
Your backend stores click ID
      │
Checkout completes
      │
      ▼
POST conversion via API
      │
Affiliate platform attributes sale
      │
Webhook back to your system
      │
Commission approved
      │
Refund? Send webhook/API update

This server-to-server approach is generally more reliable than relying solely on browser pixels, especially with modern browser privacy restrictions.

If your business processes physical products on a custom stack, my shortlist would be:

• Everflow for the best balance of flexibility and ecommerce features.
• Tapfiliate for a simpler, lower-cost implementation.
• TUNE if you expect enterprise-scale volume or need highly customized attribution and partner workflows.

If you can share your tech stack (e.g. Laravel, Node.js, .NET, Django, Rails, headless commerce, etc.) and expected affiliate volume, I can recommend the platform that will require the least custom integration work.

If you have a custom ecommerce stack and want API/webhook-based affiliate tracking (rather than relying on Shopify/WooCommerce plugins), these are among the strongest options:

If your stack is fully custom

Look for software that supports:

• Server-to-server (S2S) conversion tracking
• REST or GraphQL APIs
• Webhooks for:
  • New conversions
  • Approved commissions
  • Refunded orders
  • Affiliate updates
• Custom conversion IDs
• Custom commission logic
• Multi-touch or first/last-click attribution
• Coupon and referral code attribution
• Custom metadata (order value, products, customer ID, etc.)

Typical integration flow

1. Visitor clicks an affiliate link.
2. Affiliate platform returns a click ID (or stores it in a cookie).
3. Your ecommerce application stores that click ID with the customer's session/order.
4. When an order is paid:
   • Your backend sends a conversion via API or postback.
5. If the order is refunded or canceled:
   • Your backend notifies the affiliate platform via API/webhook to reverse the commission.

This approach is much more reliable than browser-based pixels because it works even with ad blockers and modern browser privacy restrictions.

Best choices by business size

• Small to midsize ecommerce: Trackdesk or Post Affiliate Pro
• Fast-growing DTC brand: Everflow
• Large enterprise: TUNE or Impact.com
• Affiliate network or marketplace: Affise

If you can share:

• your backend language (Node.js, PHP, .NET, Python, Java, etc.),
• your annual order volume,
• and whether you need first-click, last-click, coupon attribution, or multi-touch,

I can recommend the platform that best fits your architecture and provide an example integration flow.

If your ecommerce platform is custom-built and you want API- and webhook-driven integration with flexible attribution logic, there are several affiliate platforms that are well suited to that architecture.

For a custom stack, I'd prioritize solutions that support:

• Server-to-server conversion tracking
• REST APIs for creating affiliates, offers, commissions, and reporting
• Real-time webhooks for:
  • New affiliate registrations
  • Clicks
  • Conversions
  • Approved/rejected commissions
  • Payouts
• Custom conversion events (purchase, subscription, renewal, refund)
• First-party cookie plus server-side attribution
• Coupon-code attribution
• Multi-touch or assisted attribution if desired
• Flexible commission rules (SKU, category, customer type, LTV, etc.)

A typical integration flow looks like this:

1. Affiliate platform generates a tracking link with a click ID.
2. Customer lands on your custom storefront.
3. Your application stores the click ID (cookie, session, or user record).
4. Customer places an order.
5. Your backend sends a server-to-server conversion via the affiliate platform's API.
6. The affiliate platform attributes the sale.
7. Webhooks notify your backend when commissions are approved, adjusted, or paid.
8. Refunds or cancellations trigger additional API calls or webhooks to reverse commissions.

This approach avoids relying on client-side pixels and gives you full control over attribution.

For most custom ecommerce implementations today, my recommendations would be:

• Best overall: Everflow
• Best enterprise: TUNE or Impact.com
• Best value with strong APIs: Trackier
• Best if you're operating an affiliate network: Affise

If you expect to process 100,000+ orders/month or have complex requirements such as split commissions, cross-device attribution, or marketplace payouts, Everflow, TUNE, and Affise generally offer the most flexibility through their APIs and webhook ecosystems.