CDN caching
Caching at the edge is the single biggest performance lever: requests answered by the nearest edge never reach your origin. This page explains how the Optimi cache decides what to store and for how long.
Cache keys
A cache entry is identified by its cache key — by default the hostname,
path, and query string, plus the Accept-Encoding variant. Cookies and
authorization headers mark a response as private and bypass the cache unless a
rule explicitly allows caching.
TTLs and origin headers
The edge honors your origin's Cache-Control directives: max-age sets the
edge TTL, s-maxage overrides it for shared caches, and no-store is always
respected. Rules can extend, shorten, or force a TTL per path pattern when the
origin sends no headers.
Bypass rules
Some paths must always stay dynamic: admin areas, carts, checkout, and preview URLs. Bypass rules match on path prefixes, cookies, or query parameters and stream the response straight from the origin.
Purging
Deploying new content? Purge by URL, by path prefix, or purge everything. Targeted purges propagate across the edge in seconds, so prefer them over full purges to keep the cache warm.
Validation checklist
- Confirm the cache hit ratio rises after each rule change.
- Verify private pages never return cached content to other visitors.
- Test a targeted purge before relying on it during an incident.