Cache keys
The cache key decides when two requests share the same cached object. By default it is the scheme, host, path and full query string.
Ignoring tracking parameters
Marketing parameters such as utm_source fragment your cache. Strip them with:
"cache_key": { "query": { "exclude": ["utm_*", "fbclid", "gclid"] } }
Varying by header
To keep separate copies per language, add the header to the key:
"cache_key": { "headers": ["Accept-Language"] }
Use this sparingly: every distinct header value creates a separate copy.