400
Bad Request
4xx · Client Error
The server cannot process the request due to a client error.
What does HTTP 400 Bad Request mean?
The server cannot or will not process the request because of something perceived to be a client error, such as malformed syntax, invalid request framing, or deceptive routing.
4xx responses indicate the request was faulty: bad syntax, missing authentication, or a resource that does not exist. The fix usually lives on the client/request side.
Common causes
- Malformed JSON or invalid request body
- Missing or invalid required parameters
- Invalid headers or oversized cookies
- Incorrectly encoded URL
How to fix a 400 error
- Validate the request payload and content type
- Check required fields and parameter formats
- Clear cookies or reduce header size if they are too large
- Inspect the request in DevTools to find the malformed part
Related 4xx status codes
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