HTTP 400
Bad Request
Client Error
What does "HTTP 400 Bad Request" mean?
Plain-English Meaning
The server can't process the request because something is malformed — bad syntax, invalid request framing, etc.
Common Causes
- Malformed URL
- Oversized cookies
- Invalid JSON in request body
- Bad form data
What Users Can Do
Clear your cookies for the site. Try a different browser. Re-type the URL.
What Developers Can Do
Check your request format. Validate input before sending. Check for oversized headers.
Related Status Codes
401
Unauthorized 403
Forbidden 404
Not Found 405
Method Not Allowed 408
Request Timeout 429
Too Many Requests
Unauthorized 403
Forbidden 404
Not Found 405
Method Not Allowed 408
Request Timeout 429
Too Many Requests
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