HTTP 400 Bad Request indicates the server cannot process the request due to something perceived as a client error — malformed request syntax, invalid request message framing, or deceptive request routing. This is the generic client error response when no more specific 4xx code applies. In API design, 400 should include a descriptive error body explaining exactly what was wrong so the client can fix the request.
Response includes the status code, standard headers (including Content-Type), and a small diagnostic JSON body describing the request and returned status.
Simulator URL (copy in the app after load — not a normal link):
https://httpstatus.com/api/status/400
Example request:
curl -i "https://httpstatus.com/api/status/400"