What are the main HTTP methods used in REST APIs and their purposes?

The main HTTP methods (verbs) used in REST APIs are:

• GET: Retrieves data from the server. Should be safe and idempotent.
• POST: Creates new resources or submits data for processing.
• PUT: Updates an entire resource or creates it if it doesn't exist. Should be idempotent.
• PATCH: Partially updates a resource.
• DELETE: Removes a resource. Should be idempotent.
• HEAD: Similar to GET but returns only headers, not the body.
• OPTIONS: Returns allowed methods for a resource.

Example:

GET /users/123        # Retrieve user with ID 123
POST /users           # Create a new user
PUT /users/123        # Update entire user 123
PATCH /users/123      # Partially update user 123
DELETE /users/123     # Delete user 123