Caching is the single most effective, and most misunderstood, speed technique. It's also the reason people occasionally see an old version of a website. Understanding it takes five minutes and pays forever.
The idea in one sentence
Caching stores the finished result of a "slow" operation and serves that stored copy instead of redoing the work. A WordPress page that takes 500ms to build can be served from cache in 20ms. That's the difference between a sluggish and a snappy site.
Where caches live
| Cache | What it stores | Who clears it |
|---|---|---|
| Page cache | The finished HTML of a page | The plugin/the site admin |
| Object cache | Reusable data queries, database results | Plugin settings |
| Browser cache | Images, scripts, CSS on the visitor's device | Each visitor / their browser |
| CDN cache | Copies of your files at edge servers worldwide | The CDN dashboard/purge |
How fast sites use it
For WordPress, a caching plugin earns its keep twice over: it serves cached pages to anonymous visitors (the bulk of your traffic) while logged-in admins always see the live site. Combined with browser caching (which tells visitors' browsers how long to keep images and scripts) the perceived speed difference is dramatic.
The dark side: stale pages
Cache serves the old copy until it expires or is purged — which is why you sometimes see yesterday's site. When you edit content, remember to clear (purge) the cache. That exact problem gets its own guide: Website Showing an Old Version.
Using caching at WebFulHost
Enable a caching plugin on WordPress, or a caching layer in any app that supports one. Server-side caches are also available on some plans — read your plan's features or ask support. Whatever layer you choose, pair it with the rest of the speed playbook for the full effect.