HTTP response body for server command request

Question

I am solving one question with my team about REST API specification. We have a case where in some requests we are sending only some particular command via HTTP request for example: We are using POST (now considering PATCH request) to endpoint: /server/startSomeOperation . Backend developers told us that this request is only telling hardware to start some functionality on backend that affects the measurement of the user but it really has nothing to return. My question is: Should we (according to some REST API specification) always return body of such a request when we know that no additional returned data will be needed except HTTP status code? Until now we were strictly following the rule that every request needs to have some sort of body returned but until now every body response even when it was a command to a server made sense.

Answer 1

Should we (according to some REST API specification) always return body of such a request when we know that no additional returned data will be needed except HTTP status code?

No - it is perfectly fine to send a 204 No Content or a 205 Reset Content when the semantics of your response is well aligned with the standard meaning of those codes.

You also have the option of declaring that the "representation of the status of, or results obtained from, the action" is zero bytes long, in which case you could use a 200 OK with a Content-Length header.