Does WordPress have a Built-in REST API?

Yes, WordPress has a built-in REST API included by default since version 4.7. It allows developers to access and manage WordPress site data—such as posts, pages, users, and custom post types—using standard HTTP requests. The API follows a structured URL format, usually starting with /wp-json/, and returns responses in JSON, making it compatible with modern frontend frameworks like React, Vue, or Angular. It supports GET, POST, PUT, PATCH, and DELETE methods for reading, creating, updating, or deleting content. Developers can also create custom endpoints for plugins or themes, enabling WordPress to function as a headless CMS.