Purpose: Retrieve a resource.

Effect: Read-only, does not modify the server.

Example: GET /users/123 → Retrieves the information of the user with ID 123.

Purpose: Create a new resource.

Effect: Adds data to the server.

Example: POST /users with a JSON body → Creates a new user.

Purpose: Replace an existing resource entirely.

Effect: Completely overwrites the target resource with the sent data.

Example: PUT /users/123 → Updates the entire profile of user 123.

Purpose: Modify an existing resource partially.

Effect: Only changes the specified fields.

Example: PATCH /users/123 with { "email": "new@mail.com" } → Changes only the email.

Purpose: Delete a resource.

Effect: Removes the resource specified in the URL.

Example: DELETE /users/123 → Deletes user 123.

Purpose: Retrieve the headers of a resource (without the body).

Effect: Useful to check if a resource exists or to know its size, type, etc.

Example: HEAD /users/123 → Checks if user 123 exists.

Purpose: Request the HTTP methods supported for a resource.

Effect: Used to discover what an endpoint accepts (GET, POST, etc.), often used for CORS.

Example: OPTIONS /users → Responds with Allow: GET, POST, OPTIONS.