Choosing Between Shopware 6 Built‑In Reverse Proxy and External Varnish for Cache Invalidation

Goal

Determine the most effective caching strategy for a production Shopware 6 storefront, balancing performance, invalidation accuracy, and deployment complexity.

Constraints

• Shopware’s built‑in reverse proxy uses tag‑based invalidation that may be limited by tag cardinality and the timing of Administration updates.
• External Varnish or CDN solutions require correct trusted-proxy and host configuration to forward BAN/PURGE requests.
• Misconfigured proxies can leak personalized content between users, posing a security risk.

Unresolved Decision

Whether to rely on Shopware’s internal reverse proxy or to offload caching to a dedicated Varnish/CDN, given the differing invalidation mechanisms and operational overhead.

Specific Questions

1. Does the built‑in reverse proxy provide sufficient invalidation granularity for frequent product updates on a high‑traffic site?
2. How does Varnish handle tag‑based invalidation compared to Shopware’s internal mechanism, especially regarding TTLs and purge propagation?
3. What are the security implications of misconfigured trusted proxies when using the built‑in reverse proxy versus an external Varnish setup?