Caching stores a copy of generated content so it can be served faster on subsequent requests, without regenerating it from scratch. For WordPress, this means skipping PHP execution and database queries for repeated page views.
Types of Caching
- Browser Cache — The visitor's browser stores static files (CSS, JS, images) locally. Controlled via
Cache-ControlandExpiresheaders. - Page Cache — The server stores the fully rendered HTML page. Subsequent visitors get the cached HTML without running PHP. This is the biggest performance win.
- Object Cache — Database query results are stored in memory (Redis, Memcached). Useful for dynamic pages that can't be fully page-cached.
- CDN Cache — Static assets cached on edge servers worldwide for faster delivery.
- Opcode Cache (OPcache) — PHP bytecode is cached so the server doesn't need to recompile PHP scripts on every request.
Popular WordPress Cache Plugins
- WP Super Cache — Free, simple, by Automattic.
- W3 Total Cache — Feature-rich, supports all cache types.
- WP Rocket — Premium, user-friendly, great defaults.
- LiteSpeed Cache — Best with LiteSpeed web server, free.
What InspectWP Checks
InspectWP detects whether a WordPress caching plugin is active by looking for cache-related HTML comments, response headers, and known plugin signatures.