Speed Kit is a request-routing and cache layer for WordPress sites hosted on Plesk with the Plesk Speed Kit extension. Use requires an existing Speed Kit license. Existing license holders can continue using the add-on, but new subscriptions through WordPress are unavailable. The add-on listing warns that it has not been tested with the latest three major WordPress releases and may have compatibility issues.

How requests reach the cache

After activation, Speed Kit includes a Service Worker at /speed-kit-sw.js. It routes eligible requests from the WordPress backend through a cache synchronized with the site. Speed Kit works alongside the existing system, CDNs and load balancers, distributes synchronized content to edge locations and uses the visitor’s browser cache. Its caching technology handles static documents as well as dynamic content such as HTML, search, comments and personalization. The service also handles network protocols and tailored images.

Page coverage and controls

Speed Kit does not cache pages in every situation. The listing says caching is disabled for logged-in customers, WooCommerce sessions with entries in the basket or wishlist, and after repeated cache update failures. Settings include page and resource whitelists and blacklists, cache revalidation controls and automatic picture optimization. You can also turn off Speed Kit from its Overview screen.

Requirements and setup

Use a Plesk site with the Plesk Speed Kit extension, an existing Speed Kit license and SSL enabled. The Service Worker needs to be stored in the site’s root directory, so the plugin requires write permission there. Install and activate the plugin, then follow its setup. Speed Kit routes traffic while the site remains served from its existing IP; DNS changes are not required.

Trial terms and performance checks

The listing describes a first 10-day trial with no bank details required, followed by continued use at 9.99 € per month. It also says new subscriptions through WordPress are unavailable, so these terms may not be available to new users.

To compare performance, the listing recommends its Page Speed Analyzer or WebPageTest. It notes that many other popular performance utilities may not measure sites using Service Workers accurately.