TIL - Cache-busting CSS on GitHub Pages with site.time

Browsers cache stylesheets hard, and GitHub Pages has no asset pipeline to fingerprint filenames. Result: you push a CSS change, the site rebuilds, and half your visitors still see the old design.

The zero-dependency fix: append the build timestamp as a query string. Jekyll exposes site.time (the moment the site was built), so every deploy mints a fresh URL:

<link rel="stylesheet" href="/assets/css/style.css?v={{ site.time | date: '%s' }}">

The query string doesn’t change the file served - it just makes the URL unique per build, so caches treat it as a new resource. Same trick works for any static asset that changes between deploys.

Ops reflex worth keeping: if you can’t version the artifact, version the URL.