Caching is the single most impactful performance optimisation for WordPress, but it’s often misunderstood. There isn’t one cache — there are multiple layers, each solving a different performance bottleneck. Understanding which layer does what helps you diagnose performance issues accurately.
Object caching
Stores database query results in memory. When WordPress needs data it’s already fetched — user sessions, option values, transient data — it reads from memory instead of querying the database. This is especially impactful for WooCommerce, where product pages generate dozens of repeated queries.
Page caching stores the complete rendered HTML output of a page. When a visitor requests a page that’s been cached, the server returns the stored HTML without executing PHP or querying the database at all. This can reduce response times from 500ms+ to under 50ms.
CDN (Content Delivery Network) caching stores your assets
And optionally full pages — on edge servers distributed globally. A visitor in Sydney accessing your UK-hosted site gets served from an edge server in Australia, reducing latency from 300ms to 20ms. See how this impacts international WooCommerce sales.
The layers work together: Object caching makes dynamic page generation faster. Page caching eliminates the need for dynamic generation entirely for most visitors. CDN caching eliminates the latency of reaching your origin server. Each layer handles what the previous one can’t. View our high-performance hosting plans.
Frequently Asked Questions
What are the different types of WordPress caching?
WordPress uses four main caching layers: object caching (stores database query results in memory via Redis), page caching (stores complete rendered HTML, bypassing PHP entirely for cached requests), CDN caching (stores static assets and optionally full pages on global edge servers), and browser caching (instructs visitors’ browsers to store static files locally). Each layer solves a different bottleneck — all four together can reduce page load times by 80%+ and server resource usage by 70–90%.
What is object caching in WordPress?
Object caching stores the results of database queries in memory using Redis or Memcached. When WordPress needs data it has already fetched — user sessions, option values, product information — it reads from RAM in microseconds rather than querying the database in milliseconds. Object caching is especially impactful for WooCommerce, where product pages generate dozens of repeated queries. Without it, the same database queries run on every single page request.
What is the difference between page caching and object caching?
Page caching stores the complete rendered HTML of a page, bypassing PHP execution and database queries entirely for cached requests — reducing TTFB from 500ms+ to under 50ms. Object caching stores individual query results in memory, speeding up dynamic page generation for pages that cannot be fully page-cached (such as WooCommerce cart and checkout). Page caching has the bigger impact for static content; object caching is essential for dynamic content.
Does a CDN replace server-level caching in WordPress?
No — they solve different problems. A CDN reduces latency by serving content from edge servers close to the visitor, eliminating the round trip to your origin server. Server-level caching makes your origin fast. They complement each other: server-level caching reduces origin processing time; the CDN reduces how often visitors need to reach the origin at all.
How does LiteSpeed Cache differ from other WordPress caching plugins?
LiteSpeed Cache (LSCWP) operates at the web server level before PHP is invoked. Cached page requests are served by the web server without executing PHP at all. Other plugins like WP Rocket still require PHP to check whether a cached version exists. LiteSpeed’s approach is always faster — cached pages are served in microseconds rather than tens of milliseconds.