Wordpress REST API provides a straightforward way to interact with WordPress using HTTP requests. It allows developers to easily access and manipulate WordPress data such as posts, pages, media, and users, opening up possibilities for application development, web services, and dynamic web pages. In the following guide, you'll learn how to use the REST API for application development.

Prerequisites

• Functional installation of WordPress
• Basic knowledge of the HTTP protocol and JSON format
• Basic programming knowledge in a language that will be used for API interaction (e.g., PHP, JavaScript, Python)

1. Enabling and Configuring WordPress REST API

• By default, the WordPress REST API is active and accessible. You can verify its availability by visiting http://your-website.com/wp-json/, where your-website.com is your domain. You should see a JSON response with information about your website.

2. Basics of Working with WordPress REST API

• Endpoints: The API provides a set of endpoints for accessing and manipulating various types of data (posts, pages, users, etc.). Each endpoint has a specific URL structure, e.g., http://your-website.com/wp-json/wp/v2/posts for posts.
• HTTP Methods: To interact with data, you can use standard HTTP methods such as GET (reading data), POST (creating new records), PUT/PATCH (updating existing records), DELETE (deleting records).

3. Reading Data Using GET Requests

• To retrieve a list of all posts, send a GET request to the posts' endpoint. You can use cURL in the command line or any HTTP library in your programming language. For example:
  bash

• curl http://your-website.com/wp-json/wp/v2/posts

4. Creating New Records Using POST Requests

• To create a new post, send a POST request to the same endpoint with the necessary data in JSON format in the request body. For authorization, you may need to provide a username and password or utilize OAuth.

  curl -X POST -u "username:password" -H "Content-Type: application/json" -d '{"title":"New Post","content":"Post content"}' http://your-website.com/wp-json/wp/v2/posts
  ​

5. Updating and Deleting Data

• For updating or deleting data, use the PUT/PATCH or DELETE methods along with the ID of the specific record in the URL.

  curl -X PUT -u "username:password" -H "Content-Type: application/json" -d '{"title":"Updated Post Title"}' http://your-website.com/wp-json/wp/v2/posts/123
  ​

6. Working with Custom Post Types and Taxonomies

• If you're using custom post types or taxonomies, you can create custom endpoints for them using the register_post_type() or register_taxonomy() functions, setting show_in_rest to true.

7. Security and Authorization

• For secure operations (creating, updating, deleting), authorization is required. WordPress supports several authorization methods, including cookie and nonce, OAuth, or Basic Auth via a plugin. The choice depends on your needs and security requirements.

8. Advanced Techniques

• Customizing Responses: You can modify API responses by adding, removing, or modifying fields using filters and hooks.
• Creating Custom Endpoints: For specific needs, you can add custom endpoints using register_rest_route().

WordPress REST API offers powerful tools for developers to create dynamic and interactive applications. With extensive documentation and an active community, it's easy to find support and inspiration for your projects.