How Workers interact with Cache Rules

Your Workers script can override cache rule behavior, whether it is applied to a zone using Cloudflare or a zone that is not proxied through Cloudflare.

For example, if there is a cache rule configured to bypass cache for example.com/foo, but your Workers script sets cacheEverything: true, the script's setting will take precedence, and the request will be cached. The same applies if the request is made to a non-Cloudflare zone — the Worker's cacheEverything setting will still override.

Precedence order

Cache behavior is determined by the following order of precedence:

1. Workers script settings
2. Cache rules
3. Page rules

Cache rules override page rule settings, and Workers scripts override cache rules. Among rules at the same level, the one with the highest specificity takes priority.

Compatibility flags

This override behavior is controlled by compatibility flags:

• For the Fetch API: request_cf_overrides_cache_rules
• For the Cache API: cache_api_request_cf_overrides_cache_rules

These flags must be enabled to allow Workers scripts to override cache rules.

Compatibility date behavior

Whether these flags are enabled by default depends on your Worker's compatibility date:

• Fetch API (request_cf_overrides_cache_rules)
  • Enabled by default for compatibility dates on or after 2025-04-02.
• Cache API (cache_api_request_cf_overrides_cache_rules)
  • Enabled by default for compatibility dates on or after 2025-05-19.
  • Important: For cache_api_request_cf_overrides_cache_rules to be recognized, you must also enable cache_api_compat_flags.
    • cache_api_compat_flags enables the compatibility flag functionality for Workers. If cache_api_compat_flags is not set, then no compatibility flags — even if configured — will be recognized by the Cache API.
    • cache_api_compat_flags is enabled by default for compatibility dates on or after 2025-04-19.

If your Worker has an earlier compatibility date than the ones listed above, the corresponding flags must be manually enabled; otherwise, cache behavior will follow the original cache rules instead of the Worker's settings.

Example (Older compatibility date)

If a cache rule is configured to bypass cache for example.com/foo, and a Worker with a compatibility date of 2025-04-02 or earlier tries to set cacheEverything: true, the cache rule will take effect, and the response will not be cached.

Likewise, if using the Cache API without cache_api_compat_flags enabled, even if you enable cache_api_request_cf_overrides_cache_rules, the Cache API will not take effect.