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Performance

Cache plugins explained

How WP Rocket, WP-Optimize, and Autoptimize differ, what each setting actually does, and how to avoid the problems caching can cause.

Difficulty
Beginner

If caching is the concept, a cache plugin is the tool. This guide covers the three you're most likely to meet on a WordPress site, what separates them, and which settings cause the "I updated the page and nothing changed" problem.

Quick summary

WP Rocket is paid, does nearly everything, and is the usual recommendation. WP-Optimize is free and combines caching with image compression and database cleanup. The free Autoptimize does not do page caching — it's a companion, not a full cache plugin. Run one page-cache plugin, never two.

What these plugins actually do

Most "cache" plugins bundle several distinct jobs:

JobWhat it doesRisk if too aggressive
Page cachingSaves a finished copy of each pageVisitors see stale content
MinificationStrips whitespace from CSS/JSBroken layout or scripts
Combining filesMerges many CSS/JS files into fewBroken layout, conflicts
Lazy loadingDefers off-screen imagesImages pop in late
Database cleanupDeletes revisions, spam, transientsLost revisions
CDN integrationServes assets from edge serversMisconfigured URLs

Page caching is where most of the speed gain lives: WordPress's own performance guide sends you to caching first, as the biggest benefit for the smallest hassle. Minification and combining deliver smaller wins and cause most of the breakage we see — which is why we enable them carefully and test afterwards.

The three plugins

WP Rocket (paid)

The most complete option and the one that needs the least tuning. WP Rocket's own claim is that it caches your site automatically, with no settings to tweak, so the benefit starts on activation. It also includes cache preloading, lazy loading, a set of database cleanup options, and CDN settings for a CDN you already use.

Licence note. WP Rocket is sold as an annual licence covering a set number of websites, and it renews automatically by default. WP Rocket's own reason for the auto-renewal is so you don't lose access to some optimisation features, support and updates — so a lapsed licence costs you more than just updates. See sharing licence keys.

WP-Optimize (free, with paid tier)

Combines page caching, image compression, and database cleanup in one free plugin. A solid choice when budget matters, though several of the more advanced options (lazy loading, preloading key requests, per-role caching) are in the paid version. The database cleanup is genuinely useful on older sites that have piled up post revisions, auto-drafts, trashed posts and spam comments.

Autoptimize (free)

Does not do page caching — its own documentation tells you to add a page-caching plugin alongside it. What it does do is aggregate and minify CSS and JavaScript, minify HTML, optimise and lazy-load images, and tidy up Google Fonts. Powerful but unforgiving: it exposes options that will break a site if switched on blindly. (There is a paid Autoptimize Pro add-on that does include page caching.)

Never run two page-cache plugins

They cannot both work. Page caching in WordPress relies on a single drop-in file, advanced-cache.php, and two plugins both want to own it — WP-Optimize's own FAQ gives exactly that reason for saying no. What you get instead is unpredictable behaviour that is painful to diagnose. And if your host already provides server-level caching (most managed WordPress hosts do), you may not need a caching plugin at all — check before installing one.

"I changed the page and nothing happened"

Almost always caching, and almost always fixed in this order:

Hard-refresh your browser. Cmd + Shift + R on Mac; Ctrl + F5 or Ctrl + Shift + R on Windows. This rules out your own browser cache.

Clear the site cache. Look for "Clear cache" in the WordPress admin bar or the plugin's settings.

Clear the host's cache. Managed hosts cache independently of your plugin, usually from their own dashboard.

Clear the CDN. If you use Cloudflare or similar, purge there too.

See changes not showing for the full walkthrough.

Pages that must never be cached

Some pages break badly if a shared copy is served to everyone:

  • Cart, Checkout, and My Account pages on a store
  • Any logged-in view
  • Forms with security tokens
  • Pages showing personalised or location-specific content

WooCommerce names Cart, Checkout and My Account as the three to exclude, because they show information specific to the customer in front of them. Many cache plugins exclude them already, but WooCommerce's own advice is to check that your plugin does rather than assume it — and custom pages nearly always need excluding by hand. If your store shows another customer's cart, this is why: tell us immediately.

Common questions

Which one should I use?

If the budget allows, WP Rocket — it's the least likely to need troubleshooting. If not, WP-Optimize. Add Autoptimize only if a specific CSS/JS problem needs solving and you have somewhere to test it.

How much faster will my site get?

On an uncached site, page caching often cuts server response time dramatically. But caching can't fix oversized images, a bloated theme, or slow hosting — see what slows sites down and realistic expectations.

Is database cleanup safe?

Mostly, but it deletes post revisions permanently. Take a backup first, and keep at least a few revisions — see page and post revisions.

Do I still need a CDN?

They solve different problems, and they work happily together — WP-Optimize's documentation is explicit that page caching on your site and proxy caching at a CDN are independent of each other. A cache reduces work on your server; a CDN shortens the distance to your visitor. Sites with an international audience benefit most — see CDNs and speed.

Need a hand?

If you're stuck, email support@chykalophia.com and we'll help. Include your website address and a screenshot if you can.

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