Installation

Installation

Requirements

WordPress	6.6 or newer
PHP	8.1 or newer
Extensions	dom, json
Writable	wp-content/cache/, and wp-content/ for drop-ins
Optional	redis extension for the object cache

Works on shared hosting. Nothing requires root, a worker, or a paid tier of anything.

Install

1. Upload and activate GT Performance.
2. Open GT Performance in the admin menu.
3. Click Install page-cache drop-in.
4. Enable only the modules you have tested against your theme.

Step 3 does two things: copies advanced-cache.php into wp-content/, and adds define( 'WP_CACHE', true ); to wp-config.php. Until it runs, origin caching is configured but inactive.

If wp-config.php is not writable, add the line yourself just after the opening <?php:

define( 'WP_CACHE', true );

Verify it works

curl -sSI https://example.com/ | grep -i x-gt-cache   # MISS
curl -sSI https://example.com/ | grep -i x-gt-cache   # HIT

Test logged out — wordpress_logged_in_ is a bypass cookie, so a signed-in request will never hit.

wp gt-performance doctor

should report the drop-in owned and WP_CACHE enabled.

A sane rollout order

Each step is independently reversible. Do them one at a time and check the site in between.

1. Page cache only. Live with it for a day.
2. Media — lazy loading and dimensions. Low risk, real Core Web Vitals gain.
3. Fonts — self-host Google Fonts. Removes third-party requests.
4. CSS optimization at rollout_percent 10, then raise it.
5. JavaScript minify, then defer, then — only if you need it — delay.
6. Cloudflare or a CDN, once the origin behaves.
7. Redis object cache, if you have Redis.

Skipping to step 5 on a live store is how people conclude caching plugins are dangerous.

Uninstalling

Deactivating removes both drop-ins and the WP_CACHE line.

Deleting keeps your settings and data unless Remove all data on uninstall is enabled under Tools. With it on, uninstall removes every option, the plugin's tables, and the whole wp-content/cache/gt-performance/ directory — including the Redis configuration file, which holds credentials.

Related

Page Cache · Diagnostics · Upgrading