Code 400

HTTP 400 (Bad Request) is a client error status code indicating that the server cannot or will not process the request due to a malformed request syntax, invalid framing, or deceptive request routing. It usually points to a problem with how the browser or client formed the request.

HTTP 400 errors are identified through server log file analysis and site crawling tools like Screaming Frog. Google Search Console's Coverage report categorizes these as crawl errors, and resolving them typically involves fixing broken URL parameters, form submissions, or corrupted request headers.