Read-Heavy SaaS API

Summary

A standard SaaS API architecture optimized for read-dominant workloads. PostgreSQL serves as the primary data store, Redis provides a caching layer for hot data, connection pooling bounds database concurrency, and read replicas scale read throughput without scaling write capacity.

Problem Statement

Most SaaS APIs read far more data than they write. A single PostgreSQL primary quickly becomes a read bottleneck as concurrent users grow. Naive connection-per-request patterns exhaust the database's max_connections under modest load. The system needs a tiered read path that serves hot data from cache, distributes remaining reads across replicas, and protects the primary with a connection pool.