A bad request can occur when a user navigates to a page, or resource, and that page or resource does not exist, resulting in a 400 Bad Request error status code. Obviously, this does not give the user the best experience, but typically, the 400 Bad Request response is due to an error in the user’s request, like a typo in the URL. Sometimes these can be resolved by the user by retrying, but in other cases, they need to be resolved internally.
Avoid Bad Requests
What is a Bad Request?
Why You Should Avoid Bad Requests
Sometimes, the 400 Bad Request response is not due to a user error. In some cases, if a resource or file path was moved and not updated properly, it can cause another attempt to retrieve the resource from the server, which ends up wasting more time, slowing page load speed, and making for a bad user experience. So, to fix this issue, it is important to review your site for any broken links and updating accordingly. Running regular website speed tests or reviewing your Google Search Console can alert you to any requests that may be going to a nonexistent resource.
Lighthouse is an open-source tool that is used to run an audit against your web pages and provides scores and suggestions for improving page performance, accessibility, SEO, and more.
PageSpeed Insights is a tool created by Google that reports on the performance of a page on both mobile and desktop devices, and provides suggestions on how that page may be improved.