Which scenario would most likely trigger a 400 Bad Request response?

Which scenario would most likely trigger a 400 Bad Request response?

• A. The request URL is malformed or data is invalid
• B. The user token is expired
• C. The resource does not exist
• D. The user is not authorized

Answer: (A)

In HTTP, the 400 Bad Request status signals that the server can’t process the request because the client sent something invalid or unreadable—like broken syntax, malformed data, or data that fails validation. When the request URL is malformed or the body contains data that can’t be parsed or doesn’t match what the server expects, the server returns this 400 response to indicate the problem lies with the request itself. So, if the URL is incorrectly formed or the payload contains invalid or unparseable data, that prevents the server from understanding what you want, which is exactly when a 400 is returned. By contrast, an expired token points to authentication issues, typically resulting in 401 Unauthorized or 403 Forbidden, not a bad request. If the resource doesn’t exist, you’d see a 404 Not Found, and if the user isn’t authorized to access the resource, a 403 Forbidden would be more appropriate.

In HTTP, the 400 Bad Request status signals that the server can’t process the request because the client sent something invalid or unreadable—like broken syntax, malformed data, or data that fails validation. When the request URL is malformed or the body contains data that can’t be parsed or doesn’t match what the server expects, the server returns this 400 response to indicate the problem lies with the request itself.

So, if the URL is incorrectly formed or the payload contains invalid or unparseable data, that prevents the server from understanding what you want, which is exactly when a 400 is returned. By contrast, an expired token points to authentication issues, typically resulting in 401 Unauthorized or 403 Forbidden, not a bad request. If the resource doesn’t exist, you’d see a 404 Not Found, and if the user isn’t authorized to access the resource, a 403 Forbidden would be more appropriate.