Bloom Filter

A Bloom filter is a highly efficient, probabilistic data structure that Speed Kit uses to keep the Service Worker Cache in the browser synchronized with the server. A server cannot directly tell a browser to delete a stale file from its cache. The Bloom filter solves this by acting as a compact "checklist" of recently changed files. Before serving a file from the browser cache, the Service Worker checks this list. If the file is on the list, it knows it must re-validate it with the server. If not, the file is guaranteed to be fresh and can be served instantly. This process is far more efficient than re-validating every single cached asset.