Cache

The CMS has two layers of cache: compressed static assets (compiled CSS and JavaScript) and the API response cache (JSON responses served from APCu memory). Both are controlled from Settings → Cache.

1. The response cache

The Response Cache stores JSON responses from GET requests in APCu memory. The next identical request returns from memory in microseconds — no database, no PHP logic, no session touch.

Configuration

Field	Purpose
Enable cache	Master switch. Uncheck to disable the response cache entirely.
Cache-Timeout in seconds	The TTL for cache entries. Typical values: 300 (5 min), 3600 (1 h).

Click Save. The new settings apply on the next request.

What is cached

Cache hit conditions (all must be true):

• Method is GET.
• No user session is active ($_SESSION['userid'] is empty).
• No Backend session is active.
• No X-Api-Key header.
• TTL > 0.
• The endpoint is not in the exclude list (see below).

Responses carry an X-Cache header telling you what happened:

• X-Cache: HIT — served from memory.
• X-Cache: MISS — computed fresh, stored in memory.
• No header — not cache-eligible (session present, POST, backend endpoint, or excluded).

What is never cached

• All backend/* endpoints (hardcoded).
• Authenticated requests (any session).
• API-key requests (counted per key, not worth the shared cache).
• POST, PATCH, DELETE.
• Endpoints listed in the exclude config.

The exclude list lives in _public/extensions/core/backend/cache_settings/config/cache_exclude_endpoints.json. Prefix-matched against the request path. Typical entries: shop/cart, auth, checkout.

2. Clear the cache

The Clear cache button clears all APCu cache entries — response cache, rate-limit buckets, cached exclude lookups. Use it after:

• Bulk content changes (mass import, deploy).
• Editing runtime translations.
• Changing the exclude config.
• Any time the frontend shows stale data.

Click the button. A success banner confirms the cache was cleared.

Cache clear affects rate limits too

APCu holds more than responses — it also holds the rate-limit tokens. Clearing resets every bucket, so a DoS in progress would get a fresh budget. On a live site, prefer targeted invalidation (e.g. restart PHP-FPM only during a maintenance window).

3. Compress CSS and JS

The Compress JS and CSS button runs the asset pipeline:

• Concatenates and minifies every LESS file that compiles to frontend CSS.
• Bundles JavaScript.
• Re-generates the custom CSS for Pagebuilder spacing, flex, and custom-CSS fields.
• Compiles the custom LESS from Design Tokens (see Design Tokens).

Run this after:

• Changing design tokens in Settings → Design.
• Deploying a new theme.
• Editing LESS files directly on the server.

The compressed output lands in _public/cache/ and is served by the frontend with a long browser-cache header.

Browser cache

Compressed assets carry a long Cache-Control: max-age=31536000, immutable header. When you compress, a new hash goes into the filename — browsers load the new file automatically. Stale browser caches are not a problem for the CSS/JS layer.

For the content layer (pages, blog, product listings), the response cache + the cache-busting query on internal links handles freshness.

How APCu fits in

The response cache, the rate limiter, the exclude-config lookup, and the cache-settings TTL are all stored in APCu (shared memory within a single PHP-FPM pool). If APCu is not installed:

• Response cache becomes a no-op (still computes responses).
• Rate limiter falls back to "always allow".
• Cache-settings TTL is read from DB on every request.

Check the Task Manager → System Status panel. The APCu card must read Active. If it reads Inactive, ask your developer to install php-apcu.

Common issues

I edited content but the frontend still shows the old version. Click Clear cache. For a single page, the response cache has a 5-minute TTL by default, so waiting also works.

The frontend shows unstyled content right after a deploy. Click Compress JS and CSS. Deploys copy files but do not always re-run the compressor.

X-Cache: HIT on a page I just edited. Same cause — clear the cache or wait for the TTL.

Rate limiting seems to never trigger. APCu is disabled. Verify on Task Manager → System Status.

See also

• Task Manager — confirm APCu is active.
• Design Tokens — the "Compress CSS" button re-builds design tokens.
• Translations — clear the cache after bulk translation edits.