LiteSpeed
LiteSpeed: performance with Apache compatibility
LiteSpeed Web Server (LSWS) is a commercial web server designed as a drop-in replacement for Apache. It reads .htaccess and httpd.conf files, supports mod_rewrite and mod_security, and operates on an event-driven architecture. This allows it to handle thousands of concurrent connections with significantly lower memory usage. Its greatest advantage over Apache is the built-in LSCache, which caches full HTML pages at the server level, bypassing PHP entirely. We describe a detailed comparison of LiteSpeed and Apache in our article on LiteSpeed and OpenLiteSpeed for WordPress.
LSCache
A server-level cache that bypasses the PHP interpreter. An anonymous user's request reaches LiteSpeed, the server checks the cache, and returns the response without launching WordPress. A dedicated LiteSpeed Cache plugin for WordPress manages invalidation, supports Edge Side Includes (ESI) for dynamic fragments like WooCommerce carts, and provides image optimization via QUIC.cloud.
LSAPI vs PHP-FPM
LiteSpeed communicates with PHP through its proprietary LSAPI interface, utilizing shared memory instead of the Unix/TCP sockets used by PHP-FPM. With a large number of simultaneous dynamic requests, LSAPI exhibits higher throughput. This difference is especially noticeable under heavy traffic on WooCommerce stores and portals with many logged-in users.
License and cost
LiteSpeed Enterprise requires a license that ranges from $10 per month for the Site Owner plan (5 domains) to $92 per month for Web Host Elite. There is a free version called OpenLiteSpeed, but it offers limited Apache compatibility as it requires a restart after .htaccess changes and lacks cPanel/Plesk integration. For a single site on a VPS, OpenLiteSpeed is a reasonable choice, while for hosting providers, Enterprise is the only viable option.
When we use LiteSpeed
We choose LiteSpeed for projects expecting high traffic right from the planning stage, where quick server response time is a priority. This includes large WooCommerce stores with thousands of products, dynamic content portals, and platforms with numerous concurrent users. If the budget allows for the license fee, the benefits of LSCache and LSAPI translate directly into lower TTFB and reduced server load.