What does HTTP 400 mean?
The server cannot process the request because it is malformed or invalid.
Common causes and when you see it
Invalid JSON, missing required parameters, wrong types or an oversized header.
How to fix or handle it
Validate the request body and parameters. Return a clear error message describing what is wrong.
Test it yourself
Send a request with the online API tester, inspect the response with the HTTP header checker, or host an endpoint that returns 400 with the mock API generator to see how your app reacts.
HTTP 400 questions
The server cannot process the request because it is malformed or invalid.
Invalid JSON, missing required parameters, wrong types or an oversized header.
Validate the request body and parameters. Return a clear error message describing what is wrong.