Which response status code is used by a RESTful interface to indicate successful execution of a request?

HTTP 200 OK is the standard success response code defined by the HTTP/1.1 specification for RESTful interfaces. It signals that the server received, understood, and successfully processed the client request. Any 2xx code denotes success, with 200 being the most common general-purpose success response.

404 Not Found is a client-side error indicating the server cannot locate the requested resource, not a success condition.

405 Method Not Allowed is a client-side error indicating the HTTP method used is not supported for the target resource.

500 Internal Server Error is a server-side error indicating the server encountered an unexpected condition that prevented it from fulfilling the request.