Your API is slow, and the database is doing the same work over and over. Cache-aside with Redis is usually the first fix I reach for on a read-heavy Node.js + PostgreSQL API: 1. The request comes into Express. Check Redis first. 2. On a hit, return the cached value right away. 3. On a miss, query Postgres, store the result in Redis with a TTL, then return it. The pattern is simple. The three rules that keep it from serving stale data are the part people skip: → Always set a TTL. If an invalidation gets missed, expiry still cleans up. → Delete on write. Update the database, then delete the key. Don't patch the cached copy in place. → Guard hot keys. When a popular key expires, hundreds of requests can miss at once and hit Postgres together. A short lock or request coalescing prevents that. Caching is the easy part; invalidation is where the bugs live. If you're building a SaaS backend and want help with performance, API design or scaling, feel free to reach out. #NodeJS #Redis #PostgreSQL #BackendDevelopment #SaaS