AT8 Site Accelerator splits “make WordPress fast” into eleven independent modules that can each be switched off on their own. Every module makes an explicit trade-off, and every trade-off is documented.

Why “surgical invalidation” instead of “purge everything”

Most caching plugins delete the entire site cache whenever a post is saved. On a site with any real traffic that means: one edit = the whole cache is empty = the next batch of visitors all hit the database. The cache plugin becomes the source of the load spike.

This plugin invalidates only the URLs that are actually affected when a post is saved: the post itself, the home page, related archives, the post’s category/tag/author archives, and their paginated pages. Everything else keeps its cache.

The cache hit path

Once “advanced cache” is enabled, the plugin writes wp-content/advanced-cache.php. On a hit it sends the cached response and ends the request before WordPress finishes booting – no database queries, no theme, no other plugins.

Choosing a backend

Redis – uses a built-in pure-PHP RESP client, so the phpredis extension is not required. When several sites share one Redis instance, keys are isolated per site by a salt, and FLUSHDB is never used (it would wipe other sites).
Disk – the directory layout mirrors the URL structure (cache/at8-site-accelerator/<domain>/<path>/index.html), so “invalidate one URL” becomes “delete one directory”.
Auto – prefers Redis and falls back to disk when Redis is unreachable. The probe result is cached for one hour so that every request does not pay a connection timeout.

Modules

1. Page cache – full-page caching, TTL, separate mobile variant, URL/cookie/query-argument bypass rules. Logged-in visitors are always excluded from the shared cache.

2. Invalidation strategy – surgical invalidation (default) or full purge; whether saving a post should also purge the home page.

3. Smart preloading – prefetches the target page when a visitor hovers or touches a link, turning “click” into “instant”. Respects Save-Data and slow connections, and stops automatically while the page is hidden.

4. Browser caching – long-lived cache rules for static assets (CSS, JS, images, fonts), plus ready-to-paste nginx / Apache rule snippets (the plugin never edits your `.htaccess` on its own). HTML pages are deliberately excluded: the Free version never sends Cache-Control: public for an HTML response – page freshness is handled by the plugin’s own page cache, and anything another plugin has marked as non-cacheable is left untouched.

5. HTML minification – removes comments and redundant whitespace. The contents of pre / textarea / script / style / svg are preserved verbatim, and IE conditional comments are kept. Includes a safety valve: if the minified size drops below 40% of the original, the result is treated as broken and discarded.

6. Image lazy loading – uses the browser-native loading="lazy" attribute with no JavaScript at all. The first two above-the-fold images are explicitly marked loading="eager" so LCP is not delayed.

7. Front-end cleanup – emoji script, embeds, generator tag, jQuery Migrate, Dashicons, block editor styles, static asset query strings, Heartbeat frequency.

8. Images – automatically creates a WebP copy when a JPEG/PNG is uploaded (PNG transparency preserved). If the copy ends up larger, it is discarded.

9. Database cleanup – revisions, auto-drafts, trashed posts, spam/trashed comments, expired transients, table optimization. Everything is off by default: cleanup is destructive, so you must opt in per item. A count preview is shown before anything runs.

10. Admin cleanup – site health, activity and news widgets, version checks, oversized thumbnails.

11. Diagnostics and safety – environment health report (facts only, no scoring), conflict detection, structured logging (off by default, long hex strings and tokens are redacted before writing), and a safe mode that disables caching globally with one click.

Compatibility

Elementor – three layers of protection: check that the referenced post-*.css really exists before writing, a cache version salt, and an asynchronous style rebuild after the response ends, so visitors never get a stale page with a 404 stylesheet.
WooCommerce – cart, checkout, my account and order endpoints are never cached; changing stock invalidates exactly the affected product page.
Other caching plugins – conflicts are detected and reported (WP Rocket, LiteSpeed Cache, W3 Total Cache, WP Super Cache, Autoptimize, FlyingPress, Perfmatters, Cache Enabler, Swift Performance, Nginx Helper, Hummingbird).

What this plugin will not do

It will not modify WordPress core files.
It will not overwrite your .htaccess (it only gives you rule snippets; you decide whether to apply them).
It will not write a copy of wp-config.php anywhere. When the plugin enables WP_CACHE, the original is kept in memory only and is used to restore the file if the write or the integrity check fails – nothing is ever created next to your configuration file, not even for a moment.
It will not cache pages for logged-in users.
It will not delete your settings or cache on deactivation.
It will not delete your data on uninstall unless you explicitly turn off “keep data on uninstall”.
It does not use FLUSHDB, does not use eval, and does not call any shell command.
It contains no licence key check, no activation server, and no code that downloads or installs anything.
It contacts no external server. The only outbound link is the optional Pro information link on the plugin’s own settings screen, and it is a normal link you have to click.

Pro Version

AT8 Site Accelerator has an optional Pro edition that adds licence management, manual cache preheating and single-post post-publish preheating.

The Free edition is complete on its own: it is not a demo, nothing is locked after a trial period, and no feature asks for a purchase. Pro is installed separately, at your own initiative, by uploading it through the normal WordPress plugin installer.

AT8 Site Accelerator Pro