How do I activate REST API in WordPress?

You don’t need to manually activate the REST API in WordPress because it is built in by default since version 4.7. It is automatically enabled and ready to use for core endpoints like posts, pages, users, and media. You can access it through URLs starting with /wp-json/, such as /wp-json/wp/v2/posts. If you want custom endpoints, you can register them using the register_rest_route() function in your theme or plugin. For secured access to protected data, implement authentication methods like Application Passwords, OAuth, or JWT. No extra plugins are needed for basic REST API usage.