Signaling about 404 error in REST API

Question

What's the idiomatic way to signal the caller about an error in API, in particular, "Not found" error? Suppose, I have an url /api/vi1/check/123 . What should I return in case

1. There is no such a record with id = 123? 404 error (Http status 404)?

   status: 404 (http); data: { }

2. Or should I return OK status (Http status 200) and json with the internal status

   status: 200 (http); data: { status: 404, msg: "Not found"}?

3. And (related to 1 ) what should I return if there is no such an url ? Also Http 404 status?

Yes, I've seen the best practice videos and read the articles about REST APIs but this question wasn't answered clearly in those.

Answer 1

REST is about using HTTP's semantics. It also applies to error codes. You should use the 404 status code, and eventually a more descriptive error message in the body.

Answer 2

Yes you should return a simple 404, no more no less. (Maybe a message to go with that...) That is indicating that the resource you are looking for is not there which is good practice in REST.

Answer 3

It is also good practise not to provide any body here (like an internal status code, or message). If you really need a message in such a case (404 or 500 on an error) you can do that with an additional HTTP header field (eg X-Message: Database not available). But a 404 with empty response body is really sufficient here.