What HTTP status code should one use for invalid input

Question

In my web service I am processing input as json. What is the correct HTTP status code to use when the provided input is invalid, particularly for PUT and POST requests?

The only response code I can find that seems to apply is "400 Bad Request", but maybe there is something better?

I actually have two possibly different specific cases of this question:

a) The server doesn't like the JSON input because the attributes/ values cannot be accepted, or
b) The server cannot parse the JSON formatted input because the data is not correctly formatted as JSON.

Example: If the server expects

{ 
  "POSTDATA": {
     "val1":"123", 
     "val2":"xyz"
   }
}

and the client gives something we don't know what to do with

{ 
    "val1":"bar", 
    "val2":"biz"
}

or the client gives something borked, eg

{
"valA":"123",
skjfhasklfhakppffffzzzzz....

What to do?

I think this might elicit some strong opinions on different sides. I don't think a Bad Request code is appropriate, as that *to me* suggests that the HTTP request is bad - which it is not. I suspect others will disagree strongly. I'm not sure I'll put it on-hold as such just now, though; maybe there's a strong standard here? — Andrew Barber, Nov 06 '14 at 14:13
possible duplicate of [Right HTTP status code to wrong input](http://stackoverflow.com/questions/7939137/right-http-status-code-to-wrong-input) — Laurent S., Nov 06 '14 at 14:14
Your first error example would be a candidate for *422 Unprocessable Entity* — Alex K., Nov 06 '14 at 14:16

score 1 · Answer 1 · answered Sep 10 '19 at 11:01

1

415 Unsupported media type. The origin server is refusing to service the request because the payload is in a format not supported.

answered Sep 10 '19 at 11:01

Amjad Alwareh

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3

I don't like this. If the request specified application/text and the server requires application/json, then Yes 415 is the correct response. But if the application provides invalid json, but correctly specifies `application/json`, then the response should not be "try another media type" which is what I understand 415 to mean, it should say "your media type is correct but the data is corrupted / invalid. So I have eventually just settled on 400 invalid request. The only issue is that I use the same code for an invalid request taht is invalid based on business requirements. – The Tahaan Sep 10 '19 at 13:20

score 0 · Answer 2 · answered Sep 02 '22 at 15:03

This is an ancient question now, but for what it's worth: Today (thanks to WebDAV http extensions), this error can best be served with a 422 (Unprocessable Entity) error code, as the format and syntax are correct, but the data itself cannot be used for its intended purpose.

What HTTP status code should one use for invalid input

2 Answers2