Building APIs That Scale

Scaling an API is rarely about raw throughput first. It's about keeping the contract stable while the product underneath changes shape every quarter.

Version at the edges, not the core. Additive changes, explicit defaults, and deprecation windows buy far more time than a v2 rewrite ever will.

Measure per-endpoint latency and payload size from day one. The endpoints that hurt at scale are almost never the ones you expected — they're the innocent list views that quietly grew a dozen joins.