Caching Out

Caching Out keeps a ready-made copy of each page and serves it before WordPress loads, writes browser caching and compression rules into your server configuration, loads images, iframes and video as they are needed rather than all at once, and can minify your CSS and JavaScript. It rebuilds the copies when your content changes. It is designed to improve LCP, INP and CLS.

Performance results vary depending on hosting, theme, plugins and traffic.

We check before we touch anything

Page caching needs one file, wp-content/advanced-cache.php, and browser caching needs a block of rules in your server configuration. Either of them may already belong to another plugin.

Caching Out records a fingerprint of the drop-in file it writes and compares it before every write, overwrite or delete. If the file on disk is not the one it wrote, it leaves that file alone, does not switch page caching on, and shows a notice naming the plugin the file belongs to. The rest of the plugin keeps working.

The same rule covers your .htaccess. A marker block belonging to another plugin is never written into and never removed. Before Caching Out writes its own block it checks the result, then replaces the file in one step; if the file cannot be written, nothing is written at all, so a half-written server configuration is never left behind, and no copy of your .htaccess or wp-config.php is ever left on disk. Deactivation never edits .htaccess or wp-config.php.

Caching Out never reads, writes or removes object-cache.php.

What is on the moment you activate

• Page caching, with the drop-in installed and WP_CACHE set
• Purging when your content changes
• Browser caching: Expires headers, GZIP and Brotli, written through the checked writer described above
• Lazy loading for images, iframes and video, and missing width and height attributes added
• Hero-image priority for the image most likely to be the largest one on screen
• The Filesystem Check notice and the Page Audit of your key pages
• Your own exclusions: URLs, cookies and user agents that must never be cached, on the Cache tab

What stays off until you choose it

Anything that can change how a page looks is off until you switch it on:

• Minify CSS
• Minify JavaScript
• Defer JavaScript
• Lazy loading of CSS background images
• Database cleanup, which is manual and shows you the row counts first

The safety layer

These rules are fixed. They have no settings, they cannot be switched off, and they are the same in the free plugin and in Caching Out Pro:

• A logged-in visitor is never served a cached page
• A request carrying a session, authentication or cart cookie – including PHPSESSID – is never served from the cache and is never cached
• A response that sets a session or authentication cookie is never stored
• Cart, checkout and account pages, in WooCommerce and Easy Digital Downloads, are excluded with no configuration
• wp-admin and wp-login.php are never cached
• Only ordinary page views (GET requests) that returned 200 are cached
• Cache files are written to a temporary file and renamed into place, so a visitor never receives a half-written page
• The drop-in ownership guard described above
• define( ‘CACHINGOUT_DISABLE_CACHE’, true ); in wp-config.php disables all cache reading and writing, in every version
• Deleting the plugin removes its options, its scheduled tasks, its cache directory, the drop-in, WP_CACHE and its .htaccess block

What the free plugin does

• Page caching served from the drop-in, before WordPress and its plugins load. Cache lifespan in hours, optional separate cache files for mobile.
• Purging when a post or page is saved, trashed or restored, when a term, menu, theme, widget or customizer setting changes, when a comment is approved, and from the Purge button in the admin bar. Archives and the pages that list a changed post are purged with it.
• Browser caching: Expires headers, GZIP and Brotli for Apache through the .htaccess writer. On NGINX the documentation carries the equivalent snippet to paste into your server configuration.
• Lazy loading for images, iframes and self-hosted video, with an exclusion list, an above-the-fold allowance, missing width and height attributes added to reduce layout shift, and optional lazy loading of CSS background images.
• Hero-image priority: the image most likely to be the largest one on screen is marked high priority and preloaded, with an exclusion list.
• Minify CSS and JavaScript, and defer JavaScript, each off until you switch it on, each with its own per-file inclusion and exclusion controls. Minified copies are written to disk; the original tag keeps its attributes and only the URL changes. Already-minified files are left alone.
• Database cleanup by hand: revisions, auto-drafts, trashed posts, spam and trashed comments, and transients, with the number of rows shown before anything is deleted. Nothing is scheduled and nothing runs unattended.
• Heartbeat control and DNS prefetch for the domains you list.
• Compatibility handling for WooCommerce, Easy Digital Downloads, WPML, Polylang and page builders, which register their exclusions into the one place that decides whether a page may be cached.

Page Audit and Filesystem Check

Both are included in full, and neither needs an API key.

The Page Audit reads your tracked pages the way a visitor would – over a loopback request to your own site – and lists what it found. Where a plugin setting answers the finding, there is a button that changes that setting, and the finding is listed with the fixes. Where your theme or your host has to change something, it says so in plain words.

The Filesystem Check verifies every file the plugin needs: the drop-in, the WP_CACHE constant, the cache directory, the settings snapshot the drop-in reads and the scheduled tasks. Each row says what state it is in and what to do about it.

Caching Out Pro

The free plugin above is complete on its own and stays free. Caching Out Pro is a separate add-on, installed alongside it, that adds:

• Optimize CSS delivery, combine CSS and JS, delay JS, Google Fonts (combine and self-host), WebP and AVIF serving where copies already exist, and YouTube click-to-load
• Image compression: pick a heavy image from the Page Audit or the Media Library, see it before and after, and keep the smaller file at the same address – one image at a time, on your own server, always restorable
• Unused CSS/JS: stops named plugin files loading on pages that do not need them, with a scan, a preview, a dependency check, a never-unload list, suggested rules from a built-in catalogue and an optional weekly scan
• Activity: a record of every change the plugin makes, with one-click revert
• Performance Insights: a PageSpeed dial, a baseline, re-tests and history
• Cache preloading, a step you switch on
• Database: scheduled cleanup, orphaned metadata and table optimisation
• CDN rewriting, and purge add-ons for Cloudflare, Varnish and Sucuri
• WP-CLI commands, settings export and import, and Multisite Network Admin
• Email support from the team who built it – plus an assistant that already knows your setup. It knows which plugins you run, which settings you have on and what the Page Audit found, so you never have to explain your site before asking a question. Every answer points at the documentation or the rule it came from.

The assistant is scoped to Caching Out and your site’s configuration: 50 questions a day and 300 a month per licence. It is not a general-purpose chatbot; answers are AI-generated and can be wrong, so check anything consequential against the linked source.

Every feature in every paid plan; the paid plans differ in the number of sites and the length of support, never in what the plugin does. In both editions, anything that can change how a page looks stays off until you switch it on.

Details: https://cachingout.com/pricing/

Privacy

The free plugin does not need a licence, never contacts our servers, and makes no outbound request of its own.

The one exception is the Page Audit and the Filesystem Check, which fetch pages from your own site over a loopback request when you run them or when the tracked-page schedule runs. Nothing is sent anywhere else and nothing leaves your server.

The free plugin sends no usage data. Telemetry belongs to Caching Out Pro, where it is opt-in with the box unticked, sends aggregate figures only – never page content and never personal data – and is disabled outright by define( ‘CACHINGOUT_DISABLE_TELEMETRY’, true );.

The free plugin sets no cookies of its own. It reads cookie names on the request, because it must – a visitor carrying a session, authentication or cart cookie is never served a cached page – but no cookie value is stored, logged or sent anywhere.

Third-party libraries

The admin screens draw their icons from 63 Bootstrap Icons 1.13 glyphs (https://github.com/twbs/icons, MIT licence), kept as SVG path data in includes/class-icons.php; no icon font, stylesheet or script is shipped. Bootstrap itself is no longer used (removed in 1.22.0). Minify CSS and Minify JavaScript use matthiasmullie/minify (https://github.com/matthiasmullie/minify, MIT), shipped unminified in vendor/. assets/THIRD-PARTY-LICENSES.txt in the plugin folder names each bundled file, its version and its licence.

The plugin’s own three front-end scripts (the lazy loading helpers) are printed inline from assets/js/*.min.js; their readable source is in assets/js/src/.