Short answer: Website caching stores the finished copy of each page on the server, so the next visitor gets it in milliseconds instead of waiting for the site to build it again. On WordPress it usually comes from a caching plugin, your host or a CDN, and it needs clear rules about what never gets stored.
What page caching does
Without a cache, every visit makes the server build the page again. WordPress’s handbook calls caching the fastest way to improve performance: plugins store your posts and pages as static files and serve those, which reduces the processing load on the server.
The handbook says this can improve performance several hundred times over for fairly static pages. It also warns that pages with a lot of dynamic content make caching more complex to configure.
That saving shows up as a faster first byte, which our TTFB guide explains. A page cache is different from the browser cache, which our browser caching guide covers.
What to cache and what to skip
| Kind of visit | Store it? | Why |
|---|---|---|
| A public page for a new visitor | Yes | Everyone gets the same page |
| The same page with utm tags or ad click IDs | Yes, one copy | Campaign parameters don’t change the page |
| A logged-in user, a preview or a protected post | No | The page is different for that person |
| An error, a search result or a feed | No | They vary with each address and rarely repeat |
| The admin area, the login page and the API | No | They are for you, not for visitors |
Our own rules, read in our page cache’s code on November 4, 2026.
A page cache shares one stored copy among many people. MDN warns that personalized content stored in a shared cache may reach other users, so anything personal must skip it.
How to set up page caching
- Measure the first byte of a few pages before you change anything.
- Turn on page caching with a caching plugin, your host’s cache or a CDN. Our CDN guide covers when one is worth it.
- Exclude logged-in users, previews and any page that changes from one visitor to another.
- Let pages with campaign parameters share the same stored copy.
- Set how long copies last, and empty the cache when content changes.
- Check a response header or a second load to confirm pages come from the cache.
- Measure the first byte again, with and without the cache.
web.dev notes that for sites that update often, even a short caching time can bring noticeable gains on busy sites. Only the first visitor in that time waits for the full build.
How our own page cache works
Our site runs its own page cache. On November 4, 2026, we read five of our pages five times each from one of our other servers: with the stored copy, the first byte arrived in a median of 41 milliseconds; without it, in 1,061.
A page is stored only when nothing about the visit is personal: a normal visit, no session, preview or protected-post cookie, and no parameter other than campaign ones such as utm tags or ad click IDs, which all share one copy. Errors, search results, previews and feeds are never stored.
Copies last 8 hours, and any change that can show on a page, from a post to a menu or a setting, empties the whole cache. Every answer says HIT, MISS or BYPASS in a response header, so we can check it.
Consent needed a rule of its own. Every stored page is the version with the tracking tags switched off, and each visitor’s browser applies that visitor’s own choice. A stored copy never carries one visitor’s consent to another.
Before you rely on your page cache
- New visitors get stored pages, with a first byte in milliseconds.
- Logged-in users and previews skip the cache.
- No stored page carries one visitor’s data to another.
- Campaign parameters don’t create new copies.
- Publishing or editing a page empties the cache.
- You can tell a cached answer from a fresh one.
RememberCache what is the same for everyone, and let everything personal go straight to the server.
Our website speed guide puts caching next to the other fixes, and our web design team can set one up for you.
Quick answers about website caching
What is page caching?
The server keeps the finished copy of a page and sends it to the next visitors instead of building it again. WordPress’s handbook says this reduces the processing load on the server.
Is page caching the same as browser caching?
No. Browser caching keeps files on each visitor’s device. Page caching keeps the finished page on the server or a CDN and shares it among all visitors.
Do I need a caching plugin for WordPress?
You need a page cache, and a plugin is one way to get it. WordPress’s handbook calls caching the fastest way to improve performance; some hosts already cache pages at the server.
Can page caching show the wrong content?
Yes, if a page that changes per visitor is stored and shared. MDN warns that personalized content in a shared cache can reach other users, so logged-in visits and personal pages must skip it.
How long should pages stay cached?
Long enough to help and no longer than your content stays current. web.dev notes that even a short caching time helps busy sites; emptying the cache when you publish keeps it fresh.
Sources
Read on November 4, 2026. WordPress: Cache. MDN: HTTP caching. web.dev: Optimize Time to First Byte. Our case: our page cache’s code and settings, and five of our pages read with and without it.