HTTP 400 Bad Request indicates which condition?

• A. Bad request - The request could not be performed by the server due to bad syntax or other reason in request.
• B. Unauthorized
• C. Not Found
• D. Forbidden

Answer: (A)

HTTP 400 Bad Request means the server can’t process the request because something about the request itself is invalid or unreadable. This is a client-side problem: the request has malformed syntax, invalid framing, or bad/missing data in the body, headers, or query string. Common causes include malformed JSON or XML, incorrect Content-Type, missing required parameters, or values that don’t match what the server expects.

This is distinct from other common 4xx responses: 401 indicates authentication is required or failed, 403 means the client is authenticated but not allowed to access the resource, and 404 means the resource cannot be found. To fix a 400, review and correct the request’s syntax and data—validate JSON/XML, ensure proper encoding and headers, and verify all required fields and parameters are present and properly formatted.