WPInterface Documentation

Developer guide

Architecture, hooks and data for developers.

  • Licensing and the Lite upgrade

    The license client, updates, and how Pro takes over from the free version.

  • Coding standards and releases

    Coding standards and the release checklist.

  • Known limitations

    What the plugin deliberately does not do, and why.

  • Endpoints and front end

    AJAX, admin-post and query endpoints, and the checkout scripts.

  • Local development and testing

    Sandbox, tunnels for webhooks, logging, simulated webhooks and mocks.

  • Data reference

    Order, subscription and user meta, options, transients, scheduled actions and uninstall.

  • Hooks reference

    Filters and actions the plugin provides, with examples, and the hooks it uses.

  • Customer invoice links

    How invoice and receipt links are added to pages and emails.

  • Refund internals

    How refunds travel between WooCommerce and Paddle, and how chargebacks are handled.

  • Subscription internals

    Linking, status mapping, renewal orders, the delayed link check and restrictions.

  • Webhooks

    The endpoint, signature checks, Billing events, Classic alerts and multi-store tagging.

  • Concurrency and idempotency

    Locks, fresh reads, markers, order completion, renewals and the refund ledger.

  • Architecture

    Design principles, compatibility, files, boot sequence, drivers, API clients, gateway and blocks.

  • Settings storage

    The settings option, every key, and the helpers to read them.

  • Checkout flow

    Order lines, the three checkout entry points, subscriptions, Billing transactions, Classic pay links and payment confirmation.

  • Developer guide

    Architecture, checkout and webhook flows, stored data, safety mechanisms, hooks and local testing.