Cache busting is the process of uploading a new file to replace an existing file that is already cached. This is useful because the cache will often take a long time to expire from all of its various locations and cache busting properly ensures that any changes to a file be visible to end users sooner, rather than later.

Cache busting solves the browser caching issue by using a unique file version identifier to tell the browser that a new version of the file is available. Therefore the browser doesn’t retrieve the old file from cache but rather makes a request to the origin server for the new file.