Which of the following is NOT a legitimate HTTP method?

The reason why "UPDATE" is not a legitimate HTTP method lies in the standardized set of methods defined by the HTTP protocol. HTTP methods, also known as verbs, define the type of action that is to be performed on resources on the web. The common methods include GET, POST, DELETE, and PATCH.

GET is used to retrieve data from a server without modifying it. POST is utilized to send data to the server to create a new resource. DELETE performs the action of removing a specified resource from the server. PATCH is often used to apply partial modifications to a resource.

However, "UPDATE" is not recognized as an official HTTP method in the specification of the protocol. Instead, the appropriate method to update resources is typically PATCH or sometimes PUT, depending on whether you are updating part or all of the resource.

Understanding this distinction is crucial for anyone working with web-based APIs and integrations, as it ensures proper implementation and communication between clients and servers.