The PUT Method in HTTP
The PUT method is a fundamental request type defined within the Hypertext Transfer Protocol specification. It is primarily used to request that the state of a target Resource be created or replaced with the state defined in the request payload. In the architectural style of REST, PUT is categorized as an Idempotent operation, meaning that performing the same request multiple times will yield the same result as a single execution.
According to the IETF RFC 7231, the PUT method differs from POST in how the URI is handled. With PUT, the Client defines the exact location of the Resource, whereas with POST, the Server typically determines the destination. If the target Resource does not exist, the Server may create it, returning a 201 Created status code. If the resource is successfully updated, a 200 OK or 204 No Content is typically returned, as noted in the MDN Web Docs.
In modern Web Development, it is important to distinguish PUT from the PATCH method. While PUT is intended for full resource replacement, PATCH is used for partial modifications. Maintaining this distinction is essential for building predictable and standards-compliant APIs. When a PUT request is sent, the Client must send the entire representation of the entity; failure to do so may result in the unintentional loss of data fields not included in the request.