HTTP status codes indicate the success or failure of a request. A successful request returns a status code in the 200 range; a failed request returns a status code in the 400 or 500 range.

200 Resource found or updated
201 Resource created
400 Invalid or missing parameter
403 Permission denied
404 Route not found
412 Invalid conditional request
415 Unsupported content type
429 Rate limit exceeded
500 Server error