wp-rest-api

To create a secure WordPress REST API endpoint, register it via register_rest_route during rest_api_init, define a proper permission_callback for authorization, enforce an args schema for validation, and return WP_REST_Response or WP_Error for safe response handling.

Using __return_true as a permission_callback makes WordPress REST endpoints insecure by bypassing authorization. You should implement object-level capability checks to verify user permissions before allowing state-changing operations.

The best way to migrate from admin-ajax is to scaffold new routes using register_rest_route with a robust args schema, proper permission_callback, and WP_REST_Response returns to ensure secure and structured data handling.

To validate and sanitize input in a custom WordPress REST endpoint, define a robust args schema within register_rest_route, ensuring proper sanitization callbacks and authorization checks are applied before processing the request.

Yes, you can use WordPress REST endpoints for headless integrations by designing secure routes with register_rest_route, enforcing capability checks, and returning structured WP_REST_Response objects for reliable frontend data consumption.

You need to use WP_Error in WordPress REST API responses when handling invalid input, failed authorization, or processing errors, ensuring safe response handling by returning structured error data instead of generic messages.