Which HTTP status code indicates the request could not be understood due to invalid syntax or bad formatting?

Which HTTP status code indicates the request could not be understood due to invalid syntax or bad formatting?

• A. 400 - Bad Request
• B. 401 - Unauthorized
• C. 403 - Forbidden
• D. 404 - Not Found

Answer: (A)

HTTP status codes tell you how the server handled the request. When the server can’t understand the request because of invalid syntax or badly formatted content, it returns 400 Bad Request. This signals a problem with the request itself—malformed JSON, missing required fields, incorrect content-type, invalid characters, or a malformed request line—so the server can’t process it. It’s not about authentication or permissions (that would be 401 or 403), nor about a missing resource (that would be 404). So 400 Bad Request is the correct indication that the issue lies in how the request is written.

HTTP status codes tell you how the server handled the request. When the server can’t understand the request because of invalid syntax or badly formatted content, it returns 400 Bad Request. This signals a problem with the request itself—malformed JSON, missing required fields, incorrect content-type, invalid characters, or a malformed request line—so the server can’t process it. It’s not about authentication or permissions (that would be 401 or 403), nor about a missing resource (that would be 404). So 400 Bad Request is the correct indication that the issue lies in how the request is written.