Caching
Caching is the core mechanism that makes fast.site fast. It stores copies of your website's responses at our global Edge Servers to serve content instantly.
How caching works
Cache MISS (First Request)
fast.site forwards the request to your origin server, returns the response, and stores a copy in memory.
Cache HIT (Subsequent Requests)
The cached copy is found and served in under 5ms without contacting your origin server.
Expiration
Entries expire based on your origin's Cache-Control headers or rules you define.
Static Assets Brotli Compression
fast.site automatically applies modern Brotli compression to static text assets (CSS, JavaScript, SVG, and JSON) directly on our Edge Servers.
Brotli Quality Level 6
15-20% Smaller than GzipTuned for the optimal balance between high compression ratio (15-20% smaller than standard Gzip) and ultra-low CPU compression latency on MISS requests.
- Smaller download footprints for critical stylesheets and script bundles.
- Accelerated First Contentful Paint (FCP) and DOMContentLoaded times.
- Automatic fallback to Gzip for older clients without Brotli support.
Fast Edge Cache™ Warmer & Boot Warm
Ensure your visitors never hit an unprimed, cold cache. The Fast Edge Cache™ Warmer proactively keeps your most important pages in high-speed memory.
Background Cache Warming Worker
Our automated edge crawler periodically fetches your homepage and top 10 most visited URLs to ensure content stays fresh before expiration.
Instant Boot Warm
Following edge pod deployments or restarts, Boot Warm runs an immediate warming pass so POPs re-fill their cache in seconds.
Edge Side Includes (ESI) Hole-Punching
Deliver 100% cached HTML pages even for highly dynamic web applications, online stores, and personalized member portals.
How ESI Hole-Punching Works
Instead of bypassing the cache for logged-in users or shopping carts, fast.site caches 99% of the static HTML shell at the Edge and hole-punches only the dynamic fragments (e.g. cart counters, user greetings, CSRF tokens) in real time.
- Full-page caching benefits for Shopify, WooCommerce, Magento, and custom stores.
- Lightning-fast Time to First Byte (TTFB) under 10ms for shopping experiences.
- Dynamic personalization without sacrificing SEO performance or page speed.
Response Headers
fs-cacheValues: HIT, MISS, BYPASS. Indicates if content came from cache or origin.
fs-cache-ageNumber of seconds the cached object has been stored at the Edge.
fs-cache-hitsNumber of times the cached entry has been served. Useful for spotting hot URLs.
Cache Purging
When your website content changes, manually clear cached copies to force a fresh fetch from your origin.