ChatGPT answers, unedited

If your priority is developer extensibility—especially when building custom WordPress themes/plugins—I’d pick AffiliateWP.

My ranking for custom development

1. AffiliateWP — best overall

AffiliateWP is unusually developer-oriented. It explicitly provides hooks, filters, templates, and a REST API, and its documentation has a substantial developer/integration ecosystem. AffiliateWP AffiliateWP

The important distinction for a theme developer is that you aren't limited to styling its output. You can alter behavior and data flow:

add_filter( 'affiliatewp_some_filter', function ( $value ) {
    // Customize behavior.
    return $value;
} );

add_action( 'affiliatewp_some_action', function ( $affiliate_id ) {
    // Trigger your own functionality.
} );

It also provides customizable templates for things such as affiliate dashboards, registration/login forms and emails, which is valuable when you're trying to make the affiliate UI genuinely native to a custom theme rather than simply skinning a plugin. AffiliateWP

The REST API is another major advantage if you're building something beyond a conventional WordPress site—for example, a custom affiliate dashboard, headless frontend, React/Vue UI, external CRM integration, or custom reporting system. AffiliateWP

2. SliceWP — very strong alternative

I'd seriously consider SliceWP if your projects are predominantly WooCommerce.

Its current ecosystem includes a REST API with GET/CREATE/UPDATE/DELETE operations, custom conversion functionality, custom affiliate fields, cross-site tracking, and numerous extensions. SliceWP

Its changelog also demonstrates that they're actively adding hooks—for example, filters for affiliate registration and affiliate-account tables, plus actions around the affiliate account UI. WordPress.org

So SliceWP is not just a "configure it and forget it" plugin. It's quite hackable.

3. Solid Affiliate — interesting if you're WooCommerce-only

Solid Affiliate has a good hook architecture, with hooks following a consistent solid_affiliate/... naming scheme. For example, its documentation shows hooks around affiliate registration. Documentation | Solid Affiliate

The downside from a developer perspective is that Solid Affiliate explicitly doesn't promise stable hook documentation because its codebase is evolving. They recommend searching the codebase for do_action("solid_affiliate and apply_filters("solid_affiliate. Documentation | Solid Affiliate

That's workable for an experienced developer, but I'd prefer AffiliateWP for client projects where you want a documented extension surface.

What I'd choose for a custom theme

AffiliateWP > SliceWP > Solid Affiliate

More specifically:

• Building reusable themes/plugins for many clients: AffiliateWP
• Building heavily customized WooCommerce stores: AffiliateWP or SliceWP
• Need a custom affiliate frontend/dashboard: AffiliateWP
• Headless/custom JS frontend: AffiliateWP
• Need extensive programmatic affiliate/referral manipulation: AffiliateWP
• Want a simpler WooCommerce-centric architecture: SliceWP
• Don't mind inspecting plugin source for hooks: Solid Affiliate

One particularly important point: don't judge these plugins solely by the number of hooks. For custom WordPress development, I'd evaluate the quality of the extension architecture: whether business logic is separated cleanly, whether templates can be overridden, whether data can be accessed programmatically, whether APIs are available, and whether hooks fire at meaningful points. That's much more consequential than having 500 obscure filters. WordPress itself describes hooks as the fundamental mechanism for plugins/themes to interact and emphasizes custom hooks as an extension mechanism. WordPress Developer Resources WordPress Developer Resources

If I were starting a new agency-built custom theme today, I'd use AffiliateWP as my default unless the project had a strong reason to be SliceWP-specific.

The important distinction for a theme developer is that you aren't limited to styling its output. You can alter behavior and data flow:

If extensibility and developer control are your primary criteria, I’d put AffiliateWP first, with SliceWP and Solid Affiliate as the strongest alternatives.

My ranking for custom-theme development

1. AffiliateWP — best overall

This would be my choice if I'm building a custom WordPress theme/plugin layer and expect to substantially alter the affiliate experience.

AffiliateWP explicitly provides actions/filters, template overrides, and a REST API, and its templates cover things like affiliate dashboards, forms, emails, and account areas. It also has a fairly large add-on ecosystem. affiliatewp.com

The important advantage isn't merely "lots of hooks." It's that you can treat AffiliateWP as a backend affiliate engine while making the frontend essentially your own.

For example, I'd be comfortable building:

add_filter( 'affwp_referral_rate', function( $rate, $affiliate_id ) {
    // Custom commission logic.
    return $rate;
}, 10, 2 );

and putting your own theme/controller layer on top of the affiliate data rather than being forced into the plugin's UI.

It also has documented REST endpoints, which becomes particularly useful if you're building a custom React/JS dashboard or headless-ish frontend. affiliatewp.com

My pick for: agencies, bespoke themes, membership sites, WooCommerce + other integrations, and projects where the affiliate system is part of a larger custom application.

AffiliateWP developer documentation

2. SliceWP — arguably the best alternative

SliceWP has a particularly developer-friendly developer section. It exposes functions such as slicewp_get_affiliate(), slicewp_get_commissions(), and slicewp_get_affiliate_url(), along with actions, filters, and a REST API. slicewp.com

I actually like SliceWP if your philosophy is:

"Give me a relatively lightweight affiliate engine and let me build the presentation."

Its changelog also shows hooks being added around affiliate account tables, dashboard areas, CSV exports, settings, etc., which is a good sign for theme/plugin integration work. wordpress.org

My pick for: custom WooCommerce themes where you want less framework overhead than AffiliateWP.

SliceWP developer documentation

3. Solid Affiliate — excellent if you're WooCommerce-centric

Solid Affiliate has hooks throughout the system, and its developer documentation explicitly points developers toward do_action() and apply_filters() in the codebase. docs.solidaffiliate.com

Its big advantage is that it's deeply designed around WooCommerce, so if your custom theme is essentially a sophisticated WooCommerce storefront, it can be a very good fit.

The caveat for me as a developer is that Solid Affiliate itself says its hooks aren't currently documented as a stable reference and recommends inspecting the codebase. docs.solidaffiliate.com That's not necessarily a dealbreaker, but it makes long-term custom integrations a little less comfortable than AffiliateWP's documented developer surface.

Solid Affiliate developer documentation

Bottom line

If I were selecting one specifically as a custom WordPress theme developer:

AffiliateWP > SliceWP > Solid Affiliate

I'd choose AffiliateWP when the affiliate system needs to become deeply integrated with your custom application architecture.

I'd choose SliceWP when I want a somewhat leaner affiliate system with a good developer API/hook surface.

I'd choose Solid Affiliate when WooCommerce is the center of the universe and I want the affiliate functionality tightly coupled to it.

One important distinction: if by "affiliate plugin" you mean a plugin for managing outbound affiliate links on a content site (Amazon links, SaaS referrals, etc.), rather than a plugin for running your own affiliate program, that's a different comparison. In that case I'd rank Pretty Links / ThirstyAffiliates / AAWP-type tools very differently.

If extensibility and hooks are your primary criteria as a custom WordPress theme developer, I’d put AffiliateWP at the top, with SliceWP as the strongest alternative.

My ranking for developers

1. AffiliateWP — best overall for custom development

My pick if you're building bespoke themes/sites.

AffiliateWP explicitly provides hooks, filters, templates, and a REST API, and its developer tooling is designed for modifying essentially every part of the affiliate experience. AffiliateWP GitHub

That matters when you want to do things like:

• Build a completely custom affiliate dashboard.
• Integrate affiliate data into your theme's templates.
• Alter referral/commission behavior.
• Add custom affiliate registration fields and workflows.
• Create custom endpoints or integrations.
• Build functionality that communicates with the affiliate system programmatically.
• Replace plugin UI rather than being locked into shortcodes.

The template system is particularly attractive for theme developers because you can customize dashboard tabs, forms, emails, etc., rather than merely injecting content through hooks. AffiliateWP

affiliatewp.com

2. SliceWP — arguably the cleaner developer experience

SliceWP is very compelling if you prefer a relatively straightforward WordPress architecture.

Its developer documentation exposes both functions and actions/filters, including functions for retrieving affiliates, commissions, referral URLs, statuses, etc. SliceWP

It also has a REST API with CRUD operations through its add-on ecosystem. SliceWP

For a custom theme, that gives you a nice pattern:

$affiliate_id = slicewp_get_current_affiliate_id();

$affiliate = slicewp_get_affiliate( $affiliate_id );

$commissions = slicewp_get_commissions(
    array(
        'affiliate_id' => $affiliate_id,
    )
);

That makes it relatively easy to build your own presentation layer instead of relying heavily on the plugin's frontend.

I'd choose SliceWP over AffiliateWP if the project is relatively simple and you value a smaller, more focused system.

3. Solid Affiliate — good, particularly with WooCommerce

Solid Affiliate has a developer hook system and uses a consistent solid_affiliate/... naming scheme. For example, its documentation shows hooks around affiliate registration events. Documentation | Solid Affiliate

The downside for me as a developer is that Solid Affiliate doesn't publish a stable, comprehensive hook reference because its codebase is evolving. They actually recommend searching the source for do_action("solid_affiliate and apply_filters("solid_affiliate. Documentation | Solid Affiliate

That's workable, but if I'm building a theme/framework that I expect to maintain for years, I'd rather have a more formalized developer API.

What I'd choose

If I were building a custom WordPress theme intended to deeply integrate with an affiliate system:

AffiliateWP → first choice

SliceWP → second choice

Solid Affiliate → third choice

The important distinction is that I'm evaluating them as a developer platform, not simply as "which affiliate plugin has the best UI."

For a custom theme, I would especially prioritize:

1. Stable public hooks
2. Template overrides
3. Programmatic data-access functions
4. REST API
5. Ability to replace the frontend UI
6. Hooks around the entire affiliate lifecycle
7. Good separation between plugin logic and presentation

That's also consistent with WordPress's own extensibility model: actions let your code respond to events, while filters let you modify data, and well-designed plugins expose their own custom hooks so themes/plugins don't have to modify core plugin code. WordPress Developer Resources WordPress Developer Resources

One caveat: if by "affiliate plugin" you mean a plugin for managing affiliate links you promote (e.g. Amazon links, cloaking, link management), rather than a plugin for running your own affiliate program, then the answer changes substantially. Plugins like Pretty Links/ThirstyAffiliates are a different category.

If you're building a custom theme with your own affiliate dashboard/UI, I'd go AffiliateWP.

For a custom theme, that gives you a nice pattern:

$affiliate_id = slicewp_get_current_affiliate_id();

$affiliate = slicewp_get_affiliate( $affiliate_id );

$commissions = slicewp_get_commissions(
    array(
        'affiliate_id' => $affiliate_id,
    )
);

That makes it relatively easy to build your own presentation layer instead of relying heavily on the plugin's frontend.

I'd choose SliceWP over AffiliateWP if the project is relatively simple and you value a smaller, more focused system.

3. Solid Affiliate — good, particularly with WooCommerce

Solid Affiliate has a developer hook system and uses a consistent solid_affiliate/... naming scheme. For example, its documentation shows hooks around affiliate registration events. Documentation | Solid Affiliate

The downside for me as a developer is that Solid Affiliate doesn't publish a stable, comprehensive hook reference because its codebase is evolving. They actually recommend searching the source for do_action("solid_affiliate and apply_filters("solid_affiliate. Documentation | Solid Affiliate

That's workable, but if I'm building a theme/framework that I expect to maintain for years, I'd rather have a more formalized developer API.

What I'd choose

If I were building a custom WordPress theme intended to deeply integrate with an affiliate system:

AffiliateWP → first choice

SliceWP → second choice

Solid Affiliate → third choice

The important distinction is that I'm evaluating them as a developer platform, not simply as "which affiliate plugin has the best UI."

For a custom theme, I would especially prioritize:

1. Stable public hooks
2. Template overrides
3. Programmatic data-access functions
4. REST API
5. Ability to replace the frontend UI
6. Hooks around the entire affiliate lifecycle
7. Good separation between plugin logic and presentation

That's also consistent with WordPress's own extensibility model: actions let your code respond to events, while filters let you modify data, and well-designed plugins expose their own custom hooks so themes/plugins don't have to modify core plugin code.

If your primary criterion is developer extensibility for custom WordPress themes/plugins, my pick is AffiliateWP.

My ranking for a developer

1. AffiliateWP — best overall extensibility
2. SliceWP — best clean WordPress-native alternative
3. Solid Affiliate — excellent, particularly for WooCommerce
4. Pretty Links / ThirstyAffiliates — better for managing outbound affiliate links than running an affiliate program

1. AffiliateWP — my recommendation

AffiliateWP is the one I'd choose if I'm building a bespoke theme or client-specific affiliate system.

It exposes the three things I care about most:

• Actions and filters throughout the affiliate lifecycle
• Template overrides for frontend/admin-facing components
• REST API for building custom interfaces and integrations

AffiliateWP explicitly positions hooks, templates, and its REST API as developer tools for creating bespoke implementations. AffiliateWP AffiliateWP

That combination is particularly useful if you're building something like:

// Custom behavior when a referral is created.
add_action( 'affwp_insert_referral', function( $referral_id ) {
    // Your custom logic...
} );

The important distinction is that you're not merely styling an existing affiliate dashboard—you can build your own presentation layer while using AffiliateWP as the underlying affiliate engine.

Its documentation also has dedicated sections for integrations, affiliate accounts, referrals, reports, etc., which is useful when you're building against the internals rather than just configuring the plugin. AffiliateWP

2. SliceWP — very attractive for custom WordPress development

SliceWP is probably my second choice, and I'd seriously consider it if you prefer a simpler WordPress-native architecture.

Its developer documentation exposes functions such as:

slicewp_get_affiliate()
slicewp_get_affiliate_by_user_id()
slicewp_get_current_affiliate_id()
slicewp_get_affiliate_url()
slicewp_get_commissions()
slicewp_get_commission()

along with actions, filters, and a REST API. SliceWP

It also has hooks specifically intended for modifying the affiliate account UI, and its tables are designed to be extended with filters/custom columns. SliceWP

One interesting advantage: the REST API is available as an add-on, with CRUD operations over affiliate data. SliceWP

I'd choose SliceWP over AffiliateWP if you value a relatively straightforward WordPress API and don't need AffiliateWP's larger ecosystem.

3. Solid Affiliate

Solid Affiliate is also quite extensible, particularly if the project is heavily WooCommerce-oriented.

It has a substantial hook system. For example, its hooks follow a predictable namespace such as:

solid_affiliate/Affiliate/new_registration/success

The developers explicitly document that hooks are intended to be discovered/used throughout the codebase. Documentation | Solid Affiliate

The caveat for me is that Solid Affiliate says its hook documentation isn't considered stable because the codebase is evolving. That's not necessarily a problem, but for long-lived agency/client customizations, I'd factor that into the maintenance cost. Documentation | Solid Affiliate

What I'd use for a custom theme

If your architecture looks something like:

Custom Theme
    │
    ├── Custom affiliate dashboard
    ├── Custom registration UI
    ├── Custom referral links
    ├── Custom commission display
    ├── Custom reporting
    └── Custom WooCommerce integration
             │
             ▼
       Affiliate plugin
             │
             ▼
       Affiliate data/tracking

I'd go with AffiliateWP.

The key is to treat the affiliate plugin as your domain/data/tracking layer, rather than trying to customize its entire UI.

Your theme can then provide:

get_header();

$affiliate_id = affwp_get_affiliate_id();

$referrals = /* retrieve affiliate data */;

get_template_part(
    'template-parts/affiliate/dashboard',
    null,
    [
        'affiliate_id' => $affiliate_id,
        'referrals'   => $referrals,
    ]
);

get_footer();

That gives you much more control over the frontend than trying to override the plugin's CSS/markup.

Bottom line

For a custom-theme developer, I'd start with AffiliateWP unless there's a specific reason to prefer SliceWP. WordPress itself recommends designing extensible systems around actions and filters, so the breadth and maturity of that hook/API layer matters more to me than the out-of-the-box dashboard. developer.wordpress.org developer.wordpress.org

If you're deciding specifically for building your own affiliate dashboard in a custom theme, I can also compare the actual AffiliateWP vs SliceWP hooks/functions/data model and show which one gives you the cleanest developer architecture.

If developer extensibility is your primary criterion, I’d pick AffiliateWP.

My ranking for custom-theme development

Why AffiliateWP wins: it explicitly provides hooks, overridable templates, and a REST API, giving you several extension points rather than forcing you to work around its UI. Its API can expose affiliate data programmatically, which is particularly useful if you're building custom dashboards, account areas, headless-ish components, or theme-specific workflows. affiliatewp.com

For a custom theme, I'd especially value:

• Actions/filters for affiliate registration, referrals, commissions, payouts, etc.
• Template overrides so you can make the affiliate area actually look native to your theme.
• REST API for custom JS/React interfaces or bespoke account pages.
• A relatively mature ecosystem of add-ons rather than having to implement everything yourself. affiliatewp.com

One important exception: WooCommerce

If your projects are almost exclusively WooCommerce, I'd seriously consider Solid Affiliate instead.

Its hooks are quite extensive and are specifically exposed for developers. Its documentation shows hooks such as solid_affiliate/Affiliate/new_registration/success, and its architecture is deeply integrated with WooCommerce. affiliatewp.comdocs.solidaffiliate.com

The tradeoff is that Solid Affiliate's developers explicitly warn that its hook reference isn't considered stable because the codebase evolves rapidly. That's not necessarily a deal-breaker, but it matters if you're building a reusable commercial theme/framework that you'll maintain for years. docs.solidaffiliate.com

SliceWP is also attractive if you want something lighter. Its developer documentation exposes functions for affiliates, commissions, URLs, statuses, etc., along with filters and a REST API. slicewp.com

My recommendation

For the kind of work you're describing:

Custom WordPress themes + custom PHP + long-term maintainability → AffiliateWP

Custom WooCommerce themes where affiliate functionality is tightly coupled to WooCommerce → Solid Affiliate

Smaller/leaner custom implementations → SliceWP

I'd also evaluate the plugins by how much of their internal data model you can manipulate without touching private classes/database tables. That's often more important than the raw number of hooks.

If you're choosing one for a theme/framework you intend to reuse across multiple client sites, I can also compare AffiliateWP vs Solid Affiliate vs SliceWP at the actual developer/API level—hook naming, CRUD APIs, template overrides, database architecture, REST endpoints, custom commission logic, and how easy each is to integrate into a custom theme.

If your priority is developer extensibility rather than just ease of setup, I’d rank them:

1. AffiliateWP — best overall for custom themes/plugins
2. SliceWP — best lighter-weight alternative
3. Solid Affiliate — excellent for WooCommerce, but less attractive as a general framework

🥇 AffiliateWP

For a custom WordPress theme, AffiliateWP would be my first choice.

It explicitly provides actions/filters, overridable templates, and a REST API, which gives you several layers at which to integrate your theme or custom plugin. affiliatewp.com

That matters when you're doing things like:

• Building a completely custom affiliate dashboard
• Replacing the default affiliate UI
• Adding custom dashboard tabs/components
• Modifying referral/commission behavior
• Integrating affiliate data with your own CPTs or user meta
• Creating custom registration flows
• Connecting affiliate events to another system
• Building a headless/custom frontend via REST
• Adding your own attribution logic

The template system is particularly useful for custom themes because you're not forced to recreate everything from scratch—you can override specific pieces while retaining the plugin's underlying functionality. AffiliateWP also has a substantial add-on ecosystem. affiliatewp.com

Developer verdict: 9/10

🥈 SliceWP

SliceWP is probably the one I'd investigate if you want something simpler and more WordPress-native.

Its developer documentation exposes functions, actions, filters, and a REST API. slicewp.com

For example, it exposes functions such as:

slicewp_get_affiliates();
slicewp_get_affiliate();
slicewp_get_affiliate_by_user_id();
slicewp_get_current_affiliate_id();
slicewp_get_affiliate_url();
slicewp_get_commissions();

That makes it convenient when your custom theme needs to pull affiliate information directly into its own templates/components.

Its developer documentation is also unusually explicit about the available API surface. slicewp.com

Developer verdict: 8/10

🥉 Solid Affiliate

Solid Affiliate is very compelling if you're building specifically around WooCommerce.

It has a developer hooks reference and uses a consistent solid_affiliate/... hook naming scheme. docs.solidaffiliate.com

However, there's an important caveat for your particular question: Solid Affiliate itself warns that its hook documentation isn't currently considered stable because the codebase is evolving. docs.solidaffiliate.com

So I'd be more comfortable building a WooCommerce-specific integration around it than using it as the foundation of a generalized affiliate framework.

My choice for a custom-theme developer

One thing I'd emphasize: don't judge this solely by the number of hooks. WordPress's action/filter system is fundamentally designed for plugins and themes to modify one another, but the quality of the hook arguments, template architecture, APIs, and upgrade stability is what determines whether an integration is pleasant to maintain. developer.wordpress.org

If I were building a custom theme from scratch today, I'd choose AffiliateWP unless the project is specifically WooCommerce-centric.

If you tell me what you're actually building—e.g. custom affiliate dashboard, SaaS-style affiliate portal, WooCommerce store, custom checkout, or headless WP—I can compare the actual hook/API architecture of AffiliateWP vs SliceWP and tell you which one will be easier to extend.

If your priority is developer extensibility—especially for custom WordPress themes—I’d pick AffiliateWP.

My ranking for a theme developer

1. AffiliateWP — best overall

AffiliateWP is the one I'd choose if you're building themes that need to deeply integrate with an affiliate system.

It explicitly provides hooks, templates, and a REST API for developers. Its templates cover things like affiliate dashboards, emails, registration/login forms, and dashboard tabs, which is particularly useful when you're trying to make the affiliate experience look native to a custom theme rather than bolting a plugin UI onto it. affiliatewp.com

The REST API is another major differentiator. AffiliateWP has a mature REST API, and its newer REST API Extended add-on adds CRUD operations, making it possible to build substantially more custom frontends and external integrations. affiliatewp.com

For a theme developer, I'd particularly value:

• PHP actions/filters throughout affiliate/referral workflows
• Template overrides
• REST API
• Custom affiliate dashboard UI
• Affiliate registration customization
• Ability to build your own shortcodes/blocks around its data
• Large add-on ecosystem
• Relatively mature developer ecosystem

In other words, you can treat AffiliateWP more like an underlying affiliate framework than merely a UI plugin.

2. SliceWP — very good alternative

SliceWP is probably my second choice.

Its developer docs expose functions for affiliates, commissions, URLs, statuses, etc., as well as actions and filters. slicewp.com

The downside is that SliceWP itself acknowledges that its developer documentation is still incomplete and that many functions, filters, and actions aren't documented. slicewp.com

That's important if you're building reusable commercial themes: undocumented hooks can still be useful, but you have more maintenance risk when the plugin changes.

3. Solid Affiliate — good, but I'd be more cautious

Solid Affiliate has a respectable hook system, including namespaced hooks such as solid_affiliate/Affiliate/new_registration/success. docs.solidaffiliate.com

However, their own developer documentation explicitly says they aren't publishing stable hook documentation because the codebase is evolving. They recommend searching the codebase for do_action("solid_affiliate and apply_filters("solid_affiliate. docs.solidaffiliate.com

That's not ideal if you're developing a theme intended to survive plugin updates.

Solid Affiliate also makes the most sense when your theme is fundamentally built around WooCommerce. Its feature set and integrations are heavily oriented around that ecosystem. docs.solidaffiliate.com

What I'd use for a custom theme

If I were building a theme architecture today:

Theme → custom integration layer → AffiliateWP

rather than:

Theme → directly overrides lots of AffiliateWP internals

I'd create something like:

class MyTheme_Affiliate {

    public function init() {
        add_filter(
            'affiliatewp_some_filter',
            [$this, 'modify_affiliate_data']
        );

        add_action(
            'affiliatewp_some_action',
            [$this, 'handle_affiliate_event']
        );
    }

    public function modify_affiliate_data($data) {
        // Theme-specific customization.
        return $data;
    }

    public function handle_affiliate_event($affiliate_id) {
        // Custom theme/business logic.
    }
}

Then keep your presentation layer separate from the plugin's implementation.

That's consistent with WordPress's intended extension model: actions are for responding to events; filters are for modifying data, and custom hooks allow components to remain independently extensible. developer.wordpress.org

One important distinction

If by "affiliate plugin" you mean a plugin for managing your own affiliate program, my answer is:

AffiliateWP

If you instead mean a plugin for managing affiliate links that your site publishes (Amazon, Impact, ShareASale, etc.), I'd evaluate Pretty Links / ThirstyAffiliates / Lasso instead—the architecture and extensibility requirements are quite different.

For a developer building a commercial custom theme, though, AffiliateWP is the safest choice of the three for deep programmatic integration.

If your priority is developer extensibility—especially when building custom WordPress themes—I’d pick AffiliateWP.

My ranking for a developer

1. AffiliateWP — best overall

For a theme developer, AffiliateWP is the strongest choice. Its developer surface explicitly includes actions, filters, templates, and a REST API, which gives you several ways to integrate it without modifying plugin code. affiliatewp.com

That's particularly useful if you're building things like:

• Custom affiliate dashboards
• Custom affiliate registration/login flows
• Affiliate-specific theme templates
• Custom referral URLs
• Commission calculations
• Custom tracking/conversion events
• Integration with your own CPTs or custom checkout
• AJAX/REST-powered affiliate components
• Custom admin functionality
• Headless or decoupled integrations

The REST API is a significant differentiator if you're building a modern theme/application rather than just overriding some PHP templates.

AffiliateWP developer documentation

2. Solid Affiliate — potentially better for WooCommerce

If your custom themes are almost exclusively WooCommerce, I'd seriously consider Solid Affiliate.

Its documentation has a dedicated Developer Hooks Reference, and it is tightly integrated with WooCommerce rather than trying to support a broad collection of WordPress commerce/membership systems. docs.solidaffiliate.com

That tight integration can actually be an advantage when your theme is heavily customized around WooCommerce objects, orders, products, customers, and checkout behavior.

Solid Affiliate developer documentation

3. SliceWP — good, clean WordPress-native option

SliceWP is also quite developer-friendly. Its changelog demonstrates a steady addition of hooks for things like affiliate forms, account tables, dashboard tabs, URLs, exports, and other UI components. wordpress.org

I'd choose it when you want a relatively lightweight WordPress-native affiliate system and don't need AffiliateWP's broader ecosystem/API capabilities.

SliceWP

The important distinction

If by "affiliate plugin" you mean running an affiliate program for your own site, my recommendation is:

AffiliateWP > Solid Affiliate > SliceWP

If instead you mean a plugin for managing affiliate links that you publish to other companies, that's a different category. I'd look at Pretty Links / ThirstyAffiliates rather than AffiliateWP.

For custom themes specifically

I'd favor AffiliateWP because I wouldn't want my theme architecture to depend heavily on plugin-generated markup. I'd build a thin integration layer in the theme/plugin:

add_action( 'some_affiliatewp_hook', function () {
    // Your theme/application logic.
} );

and use the plugin's data/API/hooks to feed your own components/templates.

That's also consistent with WordPress's general extensibility model: actions and filters are intended to let themes/plugins interact without modifying the underlying plugin code. developer.wordpress.org

Bottom line: if you're an agency/developer building bespoke WordPress themes and want the plugin that gives you the most room to architect things your way, AffiliateWP is my first choice. If the project is 100% WooCommerce and you want deep WooCommerce-native behavior, I'd put Solid Affiliate very close to—or ahead of—it.

If your priority is developer extensibility—hooks, filters, template overrides, APIs, and the ability to build custom theme/client functionality—I’d pick AffiliateWP.

My ranking for a custom-theme developer

Why AffiliateWP wins

AffiliateWP is unusually developer-oriented. Its customization surface includes actions/filters, template overrides, shortcodes, blocks, and a REST API. Its own documentation specifically positions hooks, templates, and the REST API as tools for developers building bespoke functionality. affiliatewp.com

More importantly, the API isn't just an afterthought:

• Core provides REST endpoints for affiliates, referrals, visits, payouts, and creatives. affiliatewp.comaffiliatewp.comaffiliatewp.comaffiliatewp.com
• The REST API Extended add-on adds CRUD operations, so custom applications can create/update/delete affiliate data. affiliatewp.com
• The plugin has a substantial hook surface; its changelog notes documentation for 280 actions and filters in one of its developer-focused releases. affiliatewp.com
• You can customize things like affiliate-area tabs, registration forms, emails, and dashboard behavior without modifying plugin core. affiliatewp.com
• It also has a large integration/add-on ecosystem, including WooCommerce, EDD, MemberPress, Gravity Forms, WPForms, Elementor, LearnDash, etc. affiliatewp.com

For a custom theme, that means you can do things like:

add_filter( 'some_affiliatewp_filter', function ( $value ) {
    // Your theme/client-specific behavior.
    return $value;
} );

and build your own affiliate UI rather than trying to bend a plugin's prebuilt dashboard into the design.

SliceWP is the interesting alternative

SliceWP is probably my second choice. It has a dedicated developer section with functions, actions, filters, and REST API documentation. slicewp.com

However, its own documentation currently warns that its developer documentation is still in its early stages and that many functions, filters, and actions are missing. slicewp.com

So for an agency building multiple custom themes, I'd favor AffiliateWP because you're less likely to find yourself reverse-engineering undocumented internals.

I would be cautious about Solid Affiliate for this particular requirement

Solid Affiliate has hooks, but its documentation explicitly says they aren't publishing stable hook documentation because the codebase is evolving. They recommend grepping the source for do_action("solid_affiliate and apply_filters("solid_affiliate. docs.solidaffiliate.com

That's workable for an experienced developer, but it's not what I'd want as the foundation for a reusable agency theme/framework.

Bottom line

If you're building custom WordPress themes professionally, I'd choose:

1. AffiliateWP — best overall developer platform
2. SliceWP — good alternative, especially for simpler builds
3. Solid Affiliate — excellent WooCommerce product, but less attractive as a developer framework

One distinction is important: if by "affiliate plugin" you mean a plugin for managing your own affiliate program, AffiliateWP is my recommendation. If you mean a plugin for managing affiliate links to Amazon, Impact, ShareASale, etc. inside a content site, that's a different category, and I'd recommend a different stack.

If your priority is developer extensibility for custom WordPress themes/plugins, I’d rank the major options:

1. AffiliateWP — best overall
2. SliceWP — best lightweight/native-WP alternative
3. Solid Affiliate — good for WooCommerce, but less attractive for deep custom development

1. AffiliateWP — my pick for custom theme development

AffiliateWP is probably the strongest choice if you're building bespoke client themes or a custom affiliate UX.

It explicitly provides:

• Actions and filters
• Template overrides
• REST API
• A substantial add-on ecosystem
• Programmatic access to affiliate/referral data
• Integration points throughout the affiliate lifecycle

Their own developer positioning specifically calls out hooks, templates, and REST API as the mechanisms for building bespoke functionality. affiliatewp.com

That's important for a theme developer because you can keep your implementation cleanly separated:

add_filter( 'affiliatewp_some_hook', function( $value ) {
    // Customize behavior for your theme.
    return $value;
} );

And for more substantial customizations, you aren't limited to manipulating rendered HTML—you can build against the plugin's underlying data/API architecture.

I'd choose AffiliateWP if you're building:

• Custom affiliate dashboards
• Headless/custom frontend experiences
• Custom registration flows
• Affiliate-specific theme components
• Custom commission logic
• CRM/ERP integrations
• Custom reporting
• Client-specific affiliate functionality
• A reusable theme framework that needs to support affiliate functionality

2. SliceWP — excellent if you want a more WordPress-native approach

SliceWP is particularly interesting for developers because it exposes functions, actions, filters and a REST API. Its developer documentation includes functions such as slicewp_get_affiliate(), slicewp_get_commissions(), slicewp_get_affiliate_url(), etc. slicewp.comaffiliatewp.com

It also has a REST API add-on with CRUD operations for affiliate datasets. slicewp.com

The downside is documentation maturity. SliceWP itself acknowledges that its developer documentation is still incomplete and that many functions/actions/filters aren't documented. slicewp.com

So I'd characterize it as:

Great architecture + good hooks + somewhat less mature developer documentation.

That's not necessarily a dealbreaker if you're comfortable reading plugin source.

3. Solid Affiliate — capable, but I'd put it behind the first two

Solid Affiliate does expose hooks, and its hooks use a consistent solid_affiliate/... naming convention. docs.solidaffiliate.com

However, there's a significant caveat: Solid Affiliate explicitly says its hook documentation isn't considered stable and recommends searching/grepping the codebase for do_action("solid_affiliate and apply_filters("solid_affiliate. docs.solidaffiliate.com

Their roadmap has also listed Developer Actions & Filters as an area for further development. affiliatewp.comslicewp.comsolidaffiliate.com

That makes it less appealing to me if you're building a long-lived custom theme framework where you want a well-defined extension contract.

My developer-oriented comparison

One important distinction

If by "affiliate plugin" you mean affiliate-program management—where your site's users become affiliates and earn commissions—I'd go with AffiliateWP.

If instead you mean an affiliate-link management plugin for a content site—e.g. Amazon/product links, automatic link replacement, click tracking, etc.—that's a different category, and I'd evaluate plugins such as Pretty Links, ThirstyAffiliates, or Lasso instead.

For a custom WordPress theme, though, my default architecture would be:

AffiliateWP + your own theme integration layer

rather than putting AffiliateWP-specific calls throughout templates. Build something like:

your-theme/
├── inc/
│   └── affiliates/
│       ├── affiliatewp.php
│       ├── functions.php
│       └── hooks.php
└── template-parts/
    └── affiliate/
        ├── dashboard.php
        ├── referral-link.php
        └── stats.php

That gives you a clean abstraction layer, making it much easier to swap the affiliate engine later.

Bottom line: for a developer who cares primarily about hooks, APIs, template control, and long-term extensibility, I'd pick AffiliateWP. SliceWP would be my second choice, especially if you prefer a more minimal/native WordPress implementation. slicewp.comaffiliatewp.com

AffiliateWP developer documentation
SliceWP developer documentation
Solid Affiliate developer hooks

If your priority is developer extensibility—especially when you're building custom WordPress themes—I’d pick AffiliateWP.

My ranking for custom-theme development

1. AffiliateWP — best overall for developers

AffiliateWP explicitly provides actions, filters, template overrides, and a REST API, which is the combination I'd want when building a bespoke theme/plugin architecture. affiliatewp.com

The important distinction is that you're not limited to styling their frontend. You can hook into the underlying affiliate/referral behavior and build your own presentation layer.

For example, you can structure your theme/plugin around things like:

add_filter( 'affiliatewp_some_filter', function ( $value ) {
    // Modify AffiliateWP behavior.
    return $value;
} );

add_action( 'affiliatewp_some_action', function ( $affiliate_id ) {
    // React to affiliate events.
} );

And if you need an external/custom application layer, AffiliateWP has REST API support, including CRUD operations for affiliates, referrals, creatives, payouts, and visits through its extended API. affiliatewp.com

That makes it particularly attractive if you're building:

• custom affiliate dashboards
• headless-ish WordPress experiences
• custom affiliate registration flows
• bespoke commission logic
• custom reporting
• integrations with your own plugins
• custom Gutenberg/blocks implementations
• client-specific affiliate workflows

2. Solid Affiliate — very good, especially with WooCommerce

Solid Affiliate is probably my second choice, and arguably the better choice if your sites are overwhelmingly WooCommerce.

They maintain a dedicated Developer Hooks Reference, and their documentation specifically exposes hooks for extending the plugin. docs.solidaffiliate.com

It also has some nice architectural decisions for custom WordPress development: it uses normal WordPress users/roles and has affiliate groups/tags that can be leveraged in other WordPress workflows. solidaffiliate.com

One particularly nice aspect is that Solid Affiliate puts its functionality into a single plugin rather than requiring lots of separately installed add-ons. solidaffiliate.com

I'd choose it when WooCommerce + a modern affiliate portal + relatively straightforward customization matters more than having the broadest developer ecosystem.

3. SliceWP — good, but I'd put it behind the other two

SliceWP is also genuinely developer-friendly. It's open source, native to WordPress, and has a growing set of action/filter hooks. wordpress.org

For example, its changelog documents hooks added specifically so developers can extend affiliate account tables and dashboard tabs. wordpress.org

It's a good option if you want something relatively lightweight and WordPress-native, but for building a reusable custom-theme framework that you'll deploy across many client projects, I'd still favor AffiliateWP.

The important distinction

For a custom theme developer, I wouldn't judge these primarily by how many hooks they advertise. I'd look at:

1. Are hooks available at business-logic points, not just UI points?
2. Can you replace/override templates cleanly?
3. Is there a usable API/data layer?
4. Can you create your own affiliate dashboard rather than fighting the plugin's markup?
5. Can your theme/plugin survive plugin updates without hacks?
6. Can you extend it without modifying plugin files?

WordPress itself recommends hooks specifically because they let plugins/themes interact without modifying the underlying code. developer.wordpress.org

So my recommendation:

AffiliateWP if extensibility is your #1 criterion.
Solid Affiliate if you're primarily building custom WooCommerce sites.
SliceWP if you value a lighter/native WordPress approach.

If you're building a custom theme framework that needs to completely replace the affiliate plugin's frontend, I'd lean AffiliateWP pretty strongly because the combination of hooks + templates + REST API gives you the most room to make the affiliate UI essentially your own. affiliatewp.comsolidaffiliate.comsolidaffiliate.com

AffiliateWP developer documentation
Solid Affiliate developer hooks documentation
SliceWP documentation/site

If your priority is developer extensibility—hooks, filters, APIs, custom templates, and the ability to build theme/plugin integrations—I’d pick AffiliateWP.

My ranking for a custom-theme developer

Why AffiliateWP gets my vote: its developer tooling explicitly includes hooks, templates, and a REST API, and it has a large add-on ecosystem to build on. affiliatewp.com That's particularly useful when you're building a theme where you don't want to be constrained by the plugin's frontend markup.

SliceWP is probably the closest competitor. Its developer documentation exposes functions such as slicewp_get_affiliate(), slicewp_get_commissions(), slicewp_get_affiliate_url(), plus actions, filters, and a REST API. slicewp.com I'd seriously consider it if you want a relatively clean, developer-oriented foundation without as much ecosystem overhead.

Solid Affiliate is interesting for WooCommerce, but I'd put it behind the other two specifically for your requirement. Its hooks are real and use a consistent solid_affiliate/... naming scheme, but its own documentation currently says the codebase is evolving and that it doesn't publish a stable hook reference. docs.solidaffiliate.com Its roadmap also lists more comprehensive developer actions/filters as an item being developed. solidaffiliate.com

If I were building a custom theme

I'd choose AffiliateWP if I needed to do things like:

// Example architecture
add_filter( 'affiliatewp_some_value', function ( $value, $context ) {
    // Theme-specific business logic.
    return $value;
}, 10, 2 );

add_action( 'affiliatewp_some_event', function ( $affiliate_id ) {
    // Trigger custom theme/plugin behavior.
} );

More importantly, I'd avoid depending heavily on the plugin's rendered HTML. I'd build your theme's affiliate UI around the underlying affiliate data/API/hooks, with your own templates and components. That's the approach that gives you the most control when the theme evolves.

One caveat: "most hooks" isn't necessarily the same as "best architecture." What I'd look at before committing is:

1. Public functions/classes vs. reaching into internal classes.
2. Whether hooks have stable, documented parameters.
3. Template override strategy.
4. REST API coverage.
5. Database schema/API abstraction.
6. Whether frontend output can be completely replaced.
7. Whether affiliate/commission lifecycle events are exposed.
8. WooCommerce/EDD/membership integration points.
9. Whether you can build your own addon without modifying the plugin.
10. How likely updates are to break your integration.

WordPress itself recommends custom hooks as the extension mechanism precisely because they allow other plugins/themes to modify behavior without modifying the original code. developer.wordpress.org

Bottom line:

• Maximum extensibility: AffiliateWP
• Best developer-friendly alternative: SliceWP
• Best if you're exclusively WooCommerce: Solid Affiliate
• If you're building a reusable commercial theme/framework: I'd lean AffiliateWP, then create your own thin integration layer so your theme isn't tightly coupled to it.

If you tell me whether your theme is WooCommerce-only, EDD, membership/LMS, or a general-purpose theme, I can compare the actual hook/API surface of AffiliateWP vs. SliceWP and tell you which one I'd architect around.

If your priority is developer extensibility—hooks, filters, custom templates, APIs, and the ability to build a custom theme around it—I’d pick AffiliateWP overall.

My ranking for a WordPress developer

1. AffiliateWP — best overall

AffiliateWP explicitly positions itself as a framework for customization, with hooks, templates, and a REST API available for developers. affiliatewp.com

That's particularly attractive when you're building a custom theme because you can treat the affiliate system as a backend/data layer and build your own frontend rather than fighting a plugin's UI.

I'd choose it if you're doing things like:

• Custom affiliate dashboards
• Custom registration/onboarding flows
• Gutenberg/block-theme integrations
• Custom affiliate URLs
• Custom commission logic
• Connecting affiliate events to your own plugin
• Integrating with other WP/WooCommerce functionality
• Building reusable client-specific theme components

2. SliceWP — probably the best alternative

SliceWP has a dedicated developer section covering functions, actions, filters, and a REST API. affiliatewp.comslicewp.com

Its API is attractive for theme development because you get functions such as slicewp_get_affiliate(), slicewp_get_current_affiliate_id(), slicewp_get_commissions(), and slicewp_get_affiliate_url(). affiliatewp.comslicewp.com

The caveat is important: SliceWP itself says its developer documentation is still incomplete and that many functions, filters, and actions are missing from the docs. slicewp.com

So I'd use it when you want something relatively clean/lightweight and you're comfortable inspecting the source when necessary.

3. Solid Affiliate — good WooCommerce product, weaker choice for a custom framework

Solid Affiliate does have hooks, and its developers document the solid_affiliate/... hook namespace. docs.solidaffiliate.com

However, there's an interesting warning for your particular use case: their documentation says the codebase is evolving rapidly and they don't consider the hook documentation stable. docs.solidaffiliate.com Their roadmap also currently lists more developer actions/filters as something they're working toward. solidaffiliate.com

So I wouldn't make Solid Affiliate my first choice if your primary requirement is building a long-lived custom integration layer.

The important distinction

If by "affiliate plugin" you mean affiliate-program management (tracking referrals, commissions, affiliates, payouts), I'd go:

AffiliateWP > SliceWP > Solid Affiliate

But if you're talking about a content site where you're simply managing outbound affiliate product links—Amazon links, SaaS referrals, etc.—that's a different category. In that case I'd look at link-management plugins rather than AffiliateWP/SliceWP.

For a custom theme, my architecture would generally be:

AffiliateWP → custom plugin/service layer → custom theme templates/blocks

rather than putting AffiliateWP-specific calls directly throughout the theme. That gives you a much cleaner separation and makes the theme portable.

If you tell me whether you're building (a) an affiliate program where users become affiliates, or (b) a site that publishes affiliate product links, I can give you a much more specific recommendation and show what the developer API/hook experience looks like in actual code.

If extensibility and developer control are your primary criteria—not just ease of setup—I’d rank the major WordPress affiliate plugins roughly:

🥇 My pick: AffiliateWP

For a developer building custom WordPress themes, I'd choose AffiliateWP.

Its developer story is unusually strong: it explicitly provides hooks, filters, templates, and a REST API for extending the system. affiliatewp.com

That matters when you're doing things like:

• Creating completely custom affiliate dashboards
• Rendering affiliate data through your own theme templates
• Adding custom commission logic
• Integrating with custom CPTs or proprietary plugins
• Modifying affiliate URLs/tracking behavior
• Building custom registration/onboarding flows
• Adding custom REST/API functionality
• Replacing or extending frontend components without fighting the plugin

The important distinction is that you're not limited to styling their UI—you can build your own presentation layer around the underlying affiliate system.

AffiliateWP developer documentation

🥈 SliceWP is a very good alternative

SliceWP is probably the one I'd investigate next.

Its developer documentation exposes functions, actions, filters, and a REST API. slicewp.com For example, you get functions such as:

slicewp_get_affiliate()
slicewp_get_current_affiliate_id()
slicewp_get_affiliate_url()
slicewp_get_commissions()
slicewp_get_commission()

That can make it pleasant to build a custom theme layer around the plugin.

One caveat: SliceWP itself says its developer documentation is still incomplete and that many functions, filters, and actions are missing from the documentation. slicewp.com

So I'd put it slightly behind AffiliateWP for a project where you're committing to substantial custom development.

🥉 Solid Affiliate

Solid Affiliate is also quite interesting for developers, particularly if the project is WooCommerce-only.

Its hooks are fairly extensive, and its documentation shows hooks such as:

do_action(
    'solid_affiliate/Affiliate/new_registration/success',
    $affiliate_id,
    $user_id
);

It also provides a developer-focused hooks reference. docs.solidaffiliate.com

The downside is that Solid Affiliate's documentation explicitly warns that its hook API isn't considered stable because the codebase is evolving. docs.solidaffiliate.com

What I'd choose for custom theme development

If I'm building a bespoke theme/plugin stack:

AffiliateWP → SliceWP → Solid Affiliate

But there's an important qualification:

• WooCommerce + highly custom frontend: AffiliateWP or Solid Affiliate
• WooCommerce + clean/modern implementation: SliceWP
• EDD / membership / multiple integrations: AffiliateWP
• Building your own affiliate UI from scratch: AffiliateWP
• Building a reusable theme framework for multiple client sites: AffiliateWP
• Maximum control over affiliate data from PHP: AffiliateWP

WordPress itself is fundamentally designed around this extension model—actions and filters are the mechanism by which themes/plugins interact with one another. developer.wordpress.org

One thing I'd do before committing

Don't just count the number of hooks. Inspect the actual source code and database/API architecture. For a custom theme, I'd specifically evaluate:

1. Can I retrieve every piece of affiliate data without using their templates?
2. Are affiliate/commission objects exposed cleanly?
3. Can I alter commission calculation before the commission is created?
4. Can I intercept referral creation/approval/rejection?
5. Can I replace frontend templates cleanly?
6. Can I create custom affiliate endpoints?
7. Is there a REST API?
8. Are hooks fired at the points where you actually need them?
9. Are hooks documented with parameters?
10. Does the plugin maintain backward compatibility for those hooks?

AffiliateWP wins that overall developer-oriented evaluation for me.

If you're interested, I can also do a developer-focused comparison of AffiliateWP vs SliceWP vs Solid Affiliate, including their actual hooks, PHP APIs, template override systems, database schema, REST APIs, and which one I'd pick for a custom theme/framework.

For a developer building custom WordPress themes, the best affiliate plugin is usually the one that behaves like a framework rather than a UI-only plugin. You want:

• reliable actions/filters
• custom post types or data models you can extend
• REST API support
• template overrides
• database access
• custom commission logic
• compatibility with custom checkout/member systems

My ranking for developer extensibility:

1. AffiliateWP — strongest developer choice

AffiliateWP is generally my first choice when building custom themes because it exposes a mature developer API.

Strengths:

Hooks everywhere

You get actions/filters around:

• affiliate registration
• referral creation
• referral approval/rejection
• payouts
• affiliate dashboard output
• commission calculations
• tracking cookies
• affiliate metadata

Examples of the kind of customization you can do:

add_filter(
    'affwp_calc_referral_amount',
    function ($amount, $affiliate_id, $amount_raw) {
        // Custom commission logic
        return $amount * 0.8;
    },
    10,
    3
);

or:

add_action(
    'affwp_insert_referral',
    function ($referral_id) {
        // Trigger CRM sync, custom notifications, etc.
    }
);

Good fit for custom themes

You can completely replace the front-end experience:

• build your own affiliate dashboard templates
• create custom Gutenberg blocks
• expose affiliate data in REST endpoints
• create React/Vue dashboards
• integrate with custom post types

It does not force you into its default markup.

Strong integration ecosystem

Works well with:

• WooCommerce
• Easy Digital Downloads
• MemberPress
• LearnDash
• custom payment flows

For an agency building reusable themes, this matters.

2. SliceWP — cleaner modern architecture

SliceWP is worth considering if you prefer a newer codebase.

Pros:

• cleaner admin UI
• good developer documentation
• modular structure
• easier to style/customize

Cons:

• smaller ecosystem
• fewer third-party integrations than AffiliateWP

I would choose it for a custom membership/community platform where you control most of the stack.

3. Solid Affiliate — best if WooCommerce is the center

Solid Affiliate is very WooCommerce-focused.

Good:

• native WooCommerce integration
• recurring commissions
• affiliate management
• simpler customization

Less ideal if your theme needs affiliate functionality outside WooCommerce.

What I would avoid for custom theme development

Many affiliate plugins are built for site owners, not developers. Common issues:

• shortcode-heavy architecture
• limited filters
• hard-coded templates
• no service layer/API
• difficult dashboard customization

Those become painful when you are building bespoke themes.

My recommendation by project type

Agency building custom WordPress themes:
→ AffiliateWP

Custom SaaS/member platform on WordPress:
→ AffiliateWP or SliceWP

WooCommerce store with affiliates as an add-on:
→ Solid Affiliate

Need maximum code-level control:
→ AffiliateWP + your own custom plugin layer

A pattern I often recommend is keeping the affiliate plugin as the tracking/commission engine, then building your own theme UI and business rules on top through hooks rather than modifying plugin templates directly. That keeps upgrades painless.

If developer extensibility and hooks are your primary criteria, my pick is AffiliateWP.

My ranking for a custom-theme developer

Why AffiliateWP wins: its developer tooling explicitly includes hooks, templates, and a REST API, rather than treating customization as an afterthought. Its documentation also has substantial coverage around integrations, addons, referrals, affiliate accounts, etc. affiliatewp.com

AffiliateWP developer documentation

For a custom theme, that's important because you can build your own presentation layer instead of fighting the plugin's frontend. You can, for example:

• Replace/customize affiliate dashboard UI
• Inject your own affiliate components into theme templates
• Alter referral/commission data with filters
• Hook into affiliate registration and referral lifecycle events
• Build custom admin functionality
• Integrate affiliate data into your own REST endpoints
• Create client-specific addons rather than modifying plugin files

WordPress itself is designed around this model: actions let you execute custom functionality at defined points, while filters let you modify data flowing through the system. developer.wordpress.org

Solid Affiliate is the interesting alternative

If the project is strictly WooCommerce, I'd seriously consider Solid Affiliate. Its current documentation has a dedicated Developer Hooks Reference, and its architecture is particularly focused on WooCommerce. docs.solidaffiliate.com

So I'd make the decision like this:

Custom WordPress theme + potentially diverse integrations → AffiliateWP

Custom WooCommerce theme + affiliate functionality tightly coupled to WooCommerce → Solid Affiliate

Want something lighter/simpler → SliceWP

One thing I'd do before committing: inspect the actual hook reference and source architecture, rather than judging by the number of hooks advertised. For a custom theme, the quality of the hooks matters more than the raw count—particularly whether hooks expose useful objects/data at the right points in the affiliate/referral lifecycle.

If you tell me what you're trying to customize (e.g. completely custom affiliate dashboard, custom commission logic, referral tracking, registration flow, WooCommerce checkout integration), I can compare the actual hooks/API of AffiliateWP vs Solid Affiliate vs SliceWP for that use case.

For a developer building custom WordPress themes where extensibility, actions/filters, and custom integrations matter more than a turnkey UI, the strongest affiliate plugins are generally:

Best choice for a custom theme developer: AffiliateWP

For a developer, I would usually choose AffiliateWP because it was designed around WordPress conventions rather than being a closed SaaS-style system.

Strengths:

1. Extensive action/filter hooks

AffiliateWP exposes hooks around nearly every important event:

• affiliate registration
• referrals
• payouts
• commissions
• visits
• affiliate dashboard output
• integrations
• database operations

Examples of the kind of customization you can build:

add_action( 'affwp_insert_referral', function( $referral_id ) {
    // Trigger custom logic after a referral is created
});

add_filter( 'affwp_calc_referral_amount', function( $amount, $reference, $context ) {
    // Modify commission calculation
    return $amount;
}, 10, 3 );

This makes it easy to integrate with:

• custom post types
• custom membership systems
• ACF-driven sites
• bespoke checkout flows
• headless WordPress builds
• custom CRM pipelines

2. Good object-oriented architecture

AffiliateWP provides developer-friendly classes rather than forcing everything through global functions.

You can work with things like:

$affiliate = affwp_get_affiliate( $affiliate_id );

or:

$referral = affiliate_wp()->referrals->get( $referral_id );

That matters when building maintainable themes/plugins instead of one-off modifications.

3. Works well as a theme companion plugin

For custom themes, I prefer keeping affiliate logic out of the theme:

my-theme/
    functions.php
    templates/

my-site-plugin/
    affiliate-hooks.php
    integrations/
    custom-referrals.php

AffiliateWP fits this approach well. Your theme handles presentation; your site plugin handles business rules.

Runner-up: SliceWP

SliceWP is probably the closest competitor for developers.

Pros:

• cleaner modern codebase
• good WooCommerce support
• easier UI customization
• decent developer documentation

Cons:

• fewer years of ecosystem maturity
• fewer third-party integrations
• not quite as deep a hook ecosystem

I would consider it for a newer custom build where simplicity matters.

If you are building WooCommerce themes

For WooCommerce-heavy projects:

1. AffiliateWP — best overall developer choice
2. Solid Affiliate — very WooCommerce-native
3. SliceWP — clean alternative

Plugins I would avoid for custom development

Some affiliate plugins are fine for site owners but frustrating for developers because:

• business logic is buried in templates
• hooks are sparse
• database structure is difficult to extend
• customization requires overriding plugin files

For a reusable theme framework or agency workflow, I would prioritize the plugin with the strongest hook layer over the prettiest admin dashboard.

My ranking for a WordPress theme developer

1. 🥇 AffiliateWP — best hooks + ecosystem + extensibility
2. 🥈 SliceWP — cleaner modern developer experience
3. 🥉 Solid Affiliate — excellent if WooCommerce is central
4. YITH WooCommerce Affiliates
5. Easy Affiliate

If you're building agency-level custom themes, I would pair AffiliateWP with a small custom site plugin and treat the affiliate system as a service layer rather than putting customization inside the theme.

If your priority is building custom WordPress themes rather than just inserting affiliate links, the best plugin is usually the one that exposes a predictable API, WordPress-native hooks, and lets you override output without hacking core files.

Here's how I'd rank the major options from a developer's perspective:

1. AffiliateWP (Best Overall)

This is the plugin I'd recommend if you're comfortable writing PHP.

Pros

• Hundreds of WordPress actions and filters
• Object-oriented architecture
• Custom database tables
• REST API
• WP-CLI commands
• Easily extendable with add-ons
• Excellent coding standards

Typical customization:

add_filter(
    'affwp_insert_affiliate_args',
    function ($args) {

        $args['custom_meta'] = 'foo';

        return $args;
    }
);

You can also hook into:

• affiliate registration
• referral creation
• payouts
• visits
• creatives
• coupons
• commissions

It feels like a plugin written for developers.

2. Pretty Links

If you're building affiliate content sites, Pretty Links is extremely customizable.

Good features:

• Custom redirect logic
• Link tracking
• Link groups
• REST endpoints
• Plenty of filters

You can hook into:

prli_redirect_url
prli_click_recorded
prli_link_created

Easy to extend without modifying plugin files.

3. ThirstyAffiliates

Very WordPress-native.

Pros:

• CPT-based architecture
• Taxonomies
• Meta fields
• Uses familiar WP APIs

Adding custom metadata is straightforward:

register_post_meta(
    'thirstylink',
    'merchant_rating',
    [
        'show_in_rest' => true,
    ]
);

Works nicely if you're building Gutenberg blocks.

4. AffiliateWP + ACF = Excellent Combination

One setup I really like is:

AffiliateWP
+
ACF
+
Custom Theme
+
Custom Blocks

Your theme simply consumes affiliate data.

Example:

$affiliate = affwp_get_affiliate( $id );

echo esc_html( $affiliate->name );

You aren't fighting shortcodes everywhere.

5. Lasso

Lasso is polished but intentionally abstracts away much of the implementation.

Pros:

• Beautiful UI
• Product displays
• Comparison tables

Cons:

• Less hook coverage
• More closed ecosystem
• Harder to deeply customize

Great for marketers.
Less ideal for developers.

6. If You're Building a Custom Theme

I'd actually avoid plugins that require shortcodes everywhere.

Instead I'd prefer a plugin that exposes PHP functions:

$product = my_affiliate_get_product($id);

get_template_part(
    'template-parts/product-card',
    null,
    $product
);

That keeps presentation entirely inside your theme.

What Makes a Plugin "Developer Friendly"?

I usually look for these characteristics:

• Lots of do_action() and apply_filters() hooks.
• A stable PHP API instead of relying on shortcodes.
• REST API support for headless or block-based workflows.
• Custom post types or well-designed custom tables.
• Clear separation between data and presentation.
• Template override support where applicable.
• Good documentation and semantic versioning.

My Recommendation

For someone building bespoke WordPress themes:

1. AffiliateWP — Best overall for extensibility, hooks, and long-term maintainability.
2. Pretty Links — Best if your primary focus is affiliate link management within content sites.
3. ThirstyAffiliates — Great fit if you prefer working with WordPress post types and Gutenberg.
4. Lasso — Best for non-developers who want polished marketing features, but less flexible for custom theme development.

If your goal is an affiliate site with custom comparison tables, product boxes, schema markup, and theme-specific layouts (rather than running an affiliate program), I might recommend a different stack entirely than AffiliateWP.

For a developer building custom WordPress themes where extensibility, actions/filters, custom integrations, and long-term maintainability matter, the best affiliate plugin depends on whether you mean affiliate management (running an affiliate program) or affiliate links/monetization inside a theme.

For custom theme development, these are the strongest options:

My pick for custom theme developers: AffiliateWP

AffiliateWP is probably the most developer-friendly choice if you are building bespoke WordPress solutions.

Why:

1. Strong hook ecosystem

It exposes many actions and filters for:

• affiliate registration
• referral creation
• referral approval
• payouts
• commissions
• affiliate dashboards
• integrations

Examples:

add_action( 'affwp_insert_referral', function( $referral_id ) {
    // Custom logic after referral creation
});

add_filter( 'affwp_calc_referral_amount', function( $amount, $affiliate_id ) {
    return $amount * 1.1;
}, 10, 2 );

That makes it easy to wire into custom post types, membership systems, SaaS dashboards, or bespoke checkout flows.

2. Developer-first architecture

AffiliateWP uses:

• WordPress coding standards
• custom database tables
• service classes
• integrations layer
• REST API support
• extensible templates

You can override templates in your theme rather than fighting the plugin markup.

3. Good for custom theme UX

For example, you can build:

• custom affiliate dashboards
• custom referral reporting
• branded signup flows
• front-end affiliate areas
• custom commission rules

without relying heavily on shortcodes.

Solid Affiliate is a close competitor

Solid Affiliate has become popular among developers because it feels more modern and WooCommerce-focused.

Strengths:

• clean admin experience
• WooCommerce-native
• good developer hooks
• modern codebase

If your themes are primarily for WooCommerce stores, I would seriously consider it.

Plugins I would avoid for heavily custom builds

Pretty Links / ThirstyAffiliates

Great products, but they solve a different problem:

• managing outbound affiliate URLs
• cloaking links
• tracking clicks

They are not designed to power a full affiliate program.

Older all-in-one affiliate plugins

Many have:

• shortcode-heavy architecture
• limited filters
• tightly coupled templates
• poor upgrade paths

They work for site owners but become painful inside a custom theme framework.

My ranking for a WordPress theme developer

1. 🥇 AffiliateWP — best overall developer ecosystem
2. 🥈 Solid Affiliate — best modern WooCommerce-focused option
3. 🥉 SliceWP — good lightweight alternative
4. Pretty Links — best for affiliate link management
5. ThirstyAffiliates — good for editorial/content sites

If you are building themes for clients, I would choose AffiliateWP because its hook surface and ecosystem make it the least restrictive. If you are building a WooCommerce theme framework, Solid Affiliate is worth evaluating alongside it.

If you're building custom WordPress themes and plugins rather than just configuring affiliate software, I'd optimize for hook coverage, data model, and extensibility over UI.

Here's how I'd rank the major options.

1. AffiliateWP (my top recommendation)

If I'm building a bespoke client solution, this is usually where I'd start.

Why

• Extensive action/filter ecosystem
• Clean OO codebase
• Good documentation
• Predictable database schema
• Easy to override templates
• Supports custom referral generation
• Easy REST API integration
• Works well with headless or custom dashboards

Typical hooks include:

affiliatewp_insert_referral
affiliatewp_set_referral_status
affwp_track_visit
affwp_get_affiliate_rate
affwp_pre_insert_referral

and dozens more filters around:

• commission calculation
• cookies
• visits
• payouts
• registrations
• integrations

It's also straightforward to create custom integrations:

do_action(
    'affwp_set_referral_status',
    $referral_id,
    'paid'
);

or

apply_filters(
    'affwp_calc_referral_amount',
    $amount,
    $affiliate_id,
    $reference
);

This makes it feel like a "WordPress-native" plugin.

2. SliceWP

SliceWP has become surprisingly developer-friendly.

Pros:

• modern architecture
• clean code
• easier than AffiliateWP for small projects
• solid REST support
• WooCommerce integration
• Elementor support

It has fewer hooks than AffiliateWP but the architecture is clean.

If you don't need every enterprise feature, it's a pleasant codebase.

3. Solid Affiliate

Excellent if your client is already heavily invested in WooCommerce.

Pros:

• WooCommerce-first
• nice admin UX
• decent extensibility
• active development

Cons:

• not as many extension points
• more opinionated workflows

4. Ultimate Affiliate Pro

Feature-rich but less enjoyable to extend.

Typical issues:

• inconsistent naming
• business logic mixed into UI
• fewer clean filters
• difficult upgrades when heavily customized

I'd avoid it for custom development.

What I look for as a developer

For custom themes, I care about:

• Actions before/after referral creation
• Commission calculation filters
• Registration hooks
• Custom database queries
• REST endpoints
• WP-CLI support
• Template overrides
• Custom payout processors
• Webhook support
• Cron extensibility

AffiliateWP checks almost every box.

Example: Custom WooCommerce commissions

Suppose your client wants:

• 5% default
• 12% for Brand A
• 20% for Brand B
• 0% on sale items
• Lifetime customer attribution
• First-order bonus
• Different rates for subscription renewals

AffiliateWP lets you implement most of this with filters instead of modifying core files.

If you're building a SaaS-like affiliate portal

AffiliateWP is also easier to extend with:

• custom dashboards
• React admin pages
• custom REST endpoints
• GraphQL integrations
• headless front ends
• custom payout providers (Stripe, Wise, PayPal, ACH)

because the internal architecture is relatively clean.

My recommendation

For someone comfortable building custom WordPress themes and writing PHP:

1. AffiliateWP — Best balance of extensibility, hooks, documentation, and long-term maintainability.
2. SliceWP — Great modern alternative if you prefer a lighter codebase.
3. Solid Affiliate — Best when the project revolves around WooCommerce and you don't anticipate extensive customization.

If your projects routinely involve bespoke business logic, custom dashboards, or integrations with CRMs and payment providers, AffiliateWP is generally the strongest foundation. Its mature hook system and predictable architecture make it easier to extend without maintaining forks or patching core plugin code.

If you're building custom WordPress themes rather than just configuring plugins, the biggest differentiator is the quality of the plugin's architecture: hooks, filters, data model, template overrides, REST support, and whether it fights or embraces custom development.

Here's how I'd rank the major affiliate plugins from a developer's perspective.

1. AffiliateWP (My top recommendation)

If you're writing custom code regularly, this is the one I'd choose.

Pros

• Hundreds of actions and filters
• Clean object-oriented codebase
• Well-documented hook names
• Template override system
• Custom database tables (better performance)
• Easy to extend with your own integrations
• Affiliate data is accessible through classes rather than buried in post meta

Typical hooks include:

do_action( 'affwp_insert_referral', $referral_id );

do_action( 'affwp_set_affiliate_status', $affiliate_id );

apply_filters( 'affwp_calc_referral_amount', $amount, $affiliate_id );

It's easy to:

• customize commission logic
• add custom affiliate fields
• integrate with memberships
• modify payouts
• build custom dashboards
• expose data via your own endpoints

If you're comfortable writing WordPress plugins, it feels like native WP development.

2. SliceWP

A surprisingly developer-friendly plugin.

Advantages:

• Modern codebase
• Good separation of concerns
• Sensible class structure
• Lots of filters
• Easier to read than some older plugins

It doesn't have quite the ecosystem AffiliateWP has, but the code is pleasant to work with.

3. Solid Affiliate

Excellent if your primary platform is WooCommerce.

Strengths:

• modern PHP
• WooCommerce-first design
• decent hook coverage
• easy customizations

Less flexible outside WooCommerce.

4. Ultimate Affiliate Pro

Lots of features.

Less fun to develop against.

Common issues:

• large monolithic code
• inconsistent hook coverage
• many settings but fewer extension points
• more difficult to override behavior cleanly

I wouldn't choose it for a highly customized site.

5. Easy Affiliate

Good product.

Developer experience is somewhere in the middle.

Enough hooks for common customizations, but not nearly as extensible as AffiliateWP.

Things I look for as a theme/plugin developer

Custom tables

Instead of storing everything as:

wp_posts
wp_postmeta

I prefer plugins with tables like

wp_affiliates
wp_referrals
wp_visits

Queries become dramatically simpler and scale much better.

AffiliateWP and SliceWP do this well.

Hook coverage

I like seeing hooks for:

affiliate created

affiliate approved

referral generated

referral rejected

commission calculated

visit tracked

payout completed

rather than only a couple generic actions.

Filters around business logic

For example:

$commission = apply_filters(
    'my_plugin_calculate_commission',
    $commission,
    $order,
    $affiliate
);

instead of editing plugin files.

Services instead of globals

Modern plugins expose methods like

affiliatewp()->referrals->get()

instead of

global $affiliate_db;

Template overrides

A plugin should let you override:

affiliate dashboard

registration

login

tables

emails

without hacking plugin files.

If you're building bespoke client sites

My choices would be:

1. AffiliateWP — best balance of extensibility, documentation, and ecosystem for custom development.
2. SliceWP — excellent modern architecture with a clean codebase.
3. Solid Affiliate — especially if every project revolves around WooCommerce.

If you're expecting to write custom integrations, automate commission logic, expose affiliate data through custom REST endpoints or GraphQL, or build entirely custom front-end dashboards in your theme, AffiliateWP remains the strongest foundation because of its mature hook system, well-defined data model, and broad ecosystem of add-ons.

For a developer building custom WordPress themes, the best affiliate plugin is usually the one with the cleanest internal architecture, action/filter coverage, and ability to extend without fighting the UI. The strongest candidates are:

My pick for custom theme development: AffiliateWP

For a developer-first workflow, AffiliateWP is generally the strongest choice.

Why:

1. Deep WordPress hook integration

It exposes a large number of:

• do_action() hooks for extending behavior
• apply_filters() hooks for modifying data
• custom database tables
• REST API support
• template overrides

Typical developer scenarios:

add_action( 'affwp_referral_added', function( $referral_id ) {
    // Custom logic after referral creation
});

or:

add_filter( 'affwp_get_affiliate_rate', function( $rate, $affiliate_id ) {
    return $rate * 1.1;
}, 10, 2 );

This fits well with custom themes where you want affiliate behavior integrated into your own templates rather than relying on shortcodes.

2. Good separation between plugin and presentation

A custom theme can control:

• affiliate dashboards
• registration flows
• referral links
• account pages
• reporting layouts

without modifying plugin files.

You can build your own:

/your-theme/
    affiliate/
        dashboard.php
        referrals.php
        creatives.php

and keep the affiliate engine isolated.

3. Developer ecosystem

AffiliateWP has mature integrations and extension points around:

• WooCommerce
• Easy Digital Downloads
• membership plugins
• custom checkout systems
• recurring commissions

That matters if you are building reusable themes for clients.

Runner-up: SliceWP

SliceWP is worth considering if you prefer a lighter, more modern plugin architecture.

Pros:

• cleaner codebase
• easier onboarding
• good WooCommerce integration
• less "enterprise" complexity

Cons:

• smaller developer ecosystem
• fewer years of third-party extensions

If you are building a theme framework

My ranking would be:

1. AffiliateWP — best for professional custom themes, agencies, SaaS-like builds
2. SliceWP — best if you want a leaner custom implementation
3. Solid Affiliate — best when WooCommerce is the center of everything
4. Easy Affiliate — better for end users than developers

For a theme developer, I would also avoid plugins that primarily expose functionality through shortcodes/widgets. The ideal architecture is:

• plugin handles data + business logic
• theme handles markup + UX
• hooks handle customization

AffiliateWP is closest to that model.