Caching Core Principles 1. HybridCache is the default — .NET 9+ introduced as the unified caching abstraction. It combines in-memory (L1) and distributed (L2) caching with stampede protection. See ADR-004. 2. Cache reads, not writes — Cache GET operations. Invalidate on mutations. Never cache POST/PUT/DELETE responses. 3. Output caching for entire responses — When the full HTTP response can be cached (public APIs, static data), use output caching middleware. 4. Set explicit TTLs — Every cached item needs an expiration. No unbounded caches. Patterns HybridCache (Recommended Default) Cache Inva…