This plugin creates a set of REST API endpoints that correspond to CiviCRM's external scripts and its core API. It is designed for developers and administrators who need to integrate CiviCRM data and functionality with external applications, custom front-ends, or other services that communicate via HTTP. By using the standard REST architecture, it facilitates secure, programmatic access to the CRM system.

• CiviCRM API Wrapper: The primary endpoint wraps the civicrm_api3() function, allowing you to execute any CiviCRM API call (like Contact.get or Event.create) directly over REST with required authentication keys.
• Mailing Tracking Endpoints: Provides specific endpoints (civicrm/v3/url and civicrm/v3/open) to handle click and open tracking for email campaigns, which can replace the standard CiviCRM extern scripts.
• Payment Processor Handlers: Includes endpoints for processing IPN (Instant Payment Notification) calls from payment gateways like PayPal and Authorize.net, facilitating live transaction handling.
• Additional Script Replacements: Offers REST endpoints for other CiviCRM extern functions, including connection callbacks (civicrm/v3/cxn), contribution widget data (civicrm/v3/widget), and a SOAP interface (civicrm/v3/soap).
• Configuration Control: Allows administrators to control the replacement of standard mailing tracking URLs with the plugin's REST endpoints by setting a specific PHP constant, providing integration flexibility.