Powerful plugin, but the UCSS feature will cost you time

LiteSpeed Cache got our site to 95 mobile and 98 desktop on PageSpeed Insights. If you only looked at the numbers, you’d call it a five-star plugin. We’re giving it three, and the gap between those two facts is basically the whole review.

The core issue is Unique CSS. On paper it strips unused CSS per page and keeps things lean. In practice the Selector Allowlist isn’t fully trustworthy: a popup on our site quietly rendered broken for visitors for a stretch, and we didn’t catch it right away. Testing logged in as admin, everything looked fine. You have to test logged out, in a private session, every time, or you’re simply not seeing what your visitors see.

Even once you find the right fix, the caching behavior works against you. A correct CSS change can still look stale on the live page if you purge the page cache without also purging Unique CSS, or if the site isn’t freshly revisited before the next regeneration cycle runs. It’s easy to conclude a fix didn’t work when really it just hasn’t been given the chance to land yet.

What makes this genuinely frustrating over time is that none of it stays fixed. A setup that’s been solid for weeks can quietly regress with no change on your end, often because another plugin (Elementor, in our case) updated its own markup or CSS selectors. LiteSpeed’s cache has no way of knowing that happened, so it just keeps serving a version that no longer matches. That’s not entirely LiteSpeed’s fault. It’s closer to a WordPress-wide problem: a site is a stack of independently updating plugins that have no awareness of each other, and LiteSpeed just happens to be the layer where that shows up first.

So yes, the scores are real, and the plugin can genuinely deliver. But getting there took a lot of custom configuration and dev tools debugging, and staying there means you can’t treat it as solved and walk away.

We’re curious whether other people running Elementor on LiteSpeed have found a way to make these regressions less frequent, or whether periodic re-checking is simply the price of using it.