Perfmatters and Spark Speed together

The Perfmatters site does not list a page cache among its features, and the plugin itself says it is designed to work alongside your caching plugin. That is the main difference. A page cache stores the ready-made HTML of a page, so WordPress and the database do not have to work again on every visit. Perfmatters does not do that. What Perfmatters does do is decide what gets loaded on your pages. Scripts and styles of plugins that do nothing on a page can be removed per page or per post. That is work a cache plugin usually does not do, and for which Spark Speed deliberately has no solution of its own: Spark Speed works with global exclusion lists and has no separate per-page rule in the editor.

A workable split: Perfmatters decides what gets loaded, Spark Speed decides how what remains is delivered. Perfmatters does: the script manager, disabling scripts and styles on pages where they are not needed, removing WordPress bloat, and lazy loading of videos. Spark Speed does: the page cache with a privacy check on every response, determining used CSS, rebuilding (warming) the cache with a check per page, and a self-check with a decision log and safe mode. The nice thing about this split is that they do not get in each other's way. If Perfmatters disables a script on one page, Spark Speed simply sees that page as it is when warming and caches and verifies it. If a script change from Perfmatters makes a page collapse, the comparison between raw and optimised HTML does not always catch that difference, because it compares what Spark Speed itself changes. So test pages yourself after a script change.

Where both plugins can do the same thing, pick one owner. That prevents double changes and confusion about who causes what. Lazy loading: let Spark Speed handle images and iframes. It decides per image whether it is eager or lazy, with the LCP image eager and at high priority. Switch off lazy loading of images and iframes in Perfmatters and keep Perfmatters only for videos, because Spark Speed has no handling for those. Preconnect: Spark Speed does not manage preconnect hints and does not remove existing ones. Use Perfmatters for this, where you enter domains one per line. Perfmatters itself advises using fonts.gstatic.com rather than fonts.googleapis.com. Local fonts: Spark Speed puts Google Fonts on your own server by default and replaces the link with local CSS. If you use the same function in Perfmatters, choose one of the two and check in your page source that no link to Google remains. Delay JS: both Perfmatters and Spark Speed can delay scripts until interaction. Spark Speed has delay JS off by default and tests it in the optional guided optimisation. Pick one place. If you want to use the checks of Spark Speed, let Spark Speed do it; if you want per-page rules, let Perfmatters do it. Never use both for the same scripts. Used CSS and speculative loading: the same applies, one owner. Spark Speed turns speculative loading on by default on WordPress 6.8 and higher.

As of October 2026, based on the Perfmatters site and documentation and the own data of Spark Speed 0.72.0. Where we could not confirm something in the documentation, it says so.

Perfmatters is stronger at fine-grained control per page. With the script manager you disable scripts on the pages where they do nothing, for example a form plugin on pages without a form. Spark Speed has only global lists and no metabox in the editor. If you run many plugins that load scripts everywhere, you gain something here that a cache plugin cannot offer, because the problem is at the source. Perfmatters is also lighter in design: it is a set of switches and not a system with a warmer, cache and queue. That makes it easier to understand for some sites. The documentation also mentions options such as hosting Google Analytics locally and preconnect management that Spark Speed does not have.

On 9 October 2026 we read the Perfmatters home page and several documentation pages. The Perfmatters version is not shown on those pages, so we do not state one. Not all documentation pages were reachable: the script manager page only describes exceptions for logged-in and logged-out users, and for local fonts we found no working page. Those rows are therefore worded carefully. We did not install or measure Perfmatters. For Spark Speed we used our data matrix and the release notes of version 0.72.0.