Caching Strategies That Actually Work in Production

Caching is the most powerful performance tool and the most dangerous footgun in production systems. Here are the strategies that work for us and the mistakes we learned from.

Our Multi-Layer Approach

• L1: In-process memory cache for hot config and feature flags
• L2: Redis cluster for session data and frequently accessed records
• L3: CDN edge cache for static assets and public content
• L4: Database query cache for expensive aggregations

Invalidation Patterns

We use event-driven cache invalidation. When a record changes, the write path publishes an event. Cache subscribers invalidate affected keys. This gives us consistency within seconds without polling.

“There are only two hard things in computer science: cache invalidation, naming things, and off-by-one errors.”