We just shipped support for the ugliest part of HTTP: Vary – Cloudflare Blog

Automated excerpt

Vary tells a cache which request fields may affect the response, but it does not tell the cache which differences actually matter. Vary support is now available in Cache Rules on every plan. The matching Cache Rule can normalize configured fields before Cloudflare contacts the origin. Other headers are normalized only for cache matching. Configure Vary in Cache RulesIn the Cloudflare dashboard, go to Caching > Cache Rules, create or edit a rule, make the response eligible for cache, and add the Vary setting.

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