StoreEngine Free vs Pro for Developers

StoreEngine ships as two plugins — the free StoreEngine and the paid StoreEngine Pro — but from a developer's perspective they are one system. Both are addon-based, Pro depends on free, and Pro reuses the free plugin's autoloader, addon loader, schema-sync, and settings machinery. This page explains the split and how features are gated.

One framework, two plugins

Everything in StoreEngine — in both plugins — is an addon. Pro does not fork or replace the free engine; it registers additional addons into the same framework. That means:

• The free plugin owns the engine: the singleton bootstrap, autoloader, addon loader, REST layer, data layer, and the schema-sync manager.
• The Pro plugin contributes features only, as addons under its own addons/ directory, and delegates the heavy lifting back to free.

Pro's plugin header declares the dependency explicitly:

/**
 * Plugin Name: StoreEngine Pro
 * Requires Plugins: storeengine
 * …
 */

WordPress will not let Pro activate unless the free plugin is active, and Pro's code assumes free's classes are loadable.

How Pro registers its addons

Pro mirrors the free loader with its own filter. StoreEnginePro\Addons::addons_loader() builds a slug → class map through storeengine_pro/addons/loader_args, then for each addon:

$addons = apply_filters( 'storeengine_pro/addons/loader_args', [
    'membership'         => 'Membership',
    'subscription'       => 'Subscription',
    'installment-plan'   => 'InstallmentPlan',
    // …
] );

foreach ( $addons as $addon_name => $addon_class_name ) {
    $addon_root_path = STOREENGINE_PRO_ADDONS_DIR_PATH . $addon_name . '/';
    $addon_namespace = 'StoreEnginePro\\Addons\\' . $addon_class_name;

    // Register the Pro addon's namespace with the FREE plugin's autoloader.
    Autoload::get_instance()->add_namespace_directory( $addon_namespace, $addon_root_path );

    $class = $addon_namespace . '\\' . $addon_class_name;
    $class = $class::init();
    $class->run();
}

Two things to note:

1. Pro addons extend the free plugin's \StoreEngine\Classes\AbstractAddon — the same base class free addons use.
2. Pro registers its namespaces with the free plugin's Autoload::get_instance() — there is one autoloader for both plugins.

Shared schema-sync and settings

Pro addons participate in the same schema-versioning system as free addons. Both share the single storeengine_addons_db_version option, and the core manager \StoreEngine\Addons::sync_schema_for() compares each active addon's get_db_version() against it and reruns install_tables() on a mismatch. Pro simply hands its active addons to that manager:

// Pro addons share the core's single `storeengine_addons_db_version` option;
// the core manager (\StoreEngine\Addons::sync_schema_for) drives the upgrade.
add_action( 'init', [ $this, 'sync_addon_schemas' ], 4 );

The admin settings system is shared too, so Pro addons register their options and toggles through the same surfaces free addons use — a store owner enables and disables Pro addons in the same UI.

How "Pro" gating works

A feature being "Pro" means two things, both required at runtime:

1. Its addon lives in the Pro plugin (storeengine-pro/addons/{slug}/).
2. It is gated behind Pro being active and licensed.

The gate is \StoreEngine\Utils\Helper::get_addon_active_status(). Pass $is_pro = true for Pro features and it short-circuits to false unless Pro is active:

public static function get_addon_active_status( $addon_name, $is_pro = false ): bool {
    global $storeengine_addons;

    if ( $is_pro && ! self::is_active_storeengine_pro() ) {
        return false;
    }

    if ( isset( $storeengine_addons->{$addon_name} ) ) {
        return (bool) $storeengine_addons->{$addon_name};
    }

    return false;
}

Guard Pro-only code paths with the Pro flag so they degrade cleanly when Pro is absent:

use StoreEngine\Utils\Helper;

if ( Helper::get_addon_active_status( 'installment-plan', true ) ) {
    // Safe: only runs when Pro is active AND the addon is enabled.
}

Active is not the same as licensed

get_addon_active_status() confirms Pro is present and the addon is enabled. Licensed Pro features additionally validate a license key at runtime. In development you can load Pro's code by activating the plugin, but license-gated behavior may remain inactive until a valid license is applied.

Addon reference: free vs Pro

Several slugs appear in both plugins (for example membership, subscription, multi-vendor, funnel-builder, ai, inventory/inventory-pro, seeder). In those cases the free addon provides the baseline and the Pro addon extends it — enabling Pro unlocks the advanced surface of the same feature.

Free addons (storeengine/addons/)	Pro addons (storeengine-pro/addons/)
affiliate	abandoned-cart
ai	advanced-coupon
brand	ai
catalog-mode	cost-profit
couriers	dropshipping
csv	dynamic-pricing
email	fraud-shield
embeddable-checkout	funnel-builder
eu-compliance	installment-plan
eu-vat	inventory-pro
funnel-builder	license-management
gdpr	membership
instant-checkout	multi-vendor
inventory	order-bumps
invoice	pos
membership	returns
migration-tool	role-permission
multi-currency	seeder
multi-vendor	subscription
paddle	suppliers
paypal	verification
razorpay
seeder
seo
stripe
subscription
webhooks

Payment gateways are free addons

The bundled payment gateways — Stripe, PayPal, Razorpay, and Paddle — ship as free addons. Adding a new gateway does not require Pro; see Payment Gateways.

Where to go next

• Building Addons — build an addon for either plugin using this shared framework.
• Architecture Overview — how the addon framework fits the whole engine.
• Plugin Structure — where free and Pro code live on disk.