What architecture survives real growth?
Modular domains with explicit API boundaries, typed contracts, and observability hooks from the first production deploy.
Monoliths are fine until boundaries blur. I structure React/Next apps so new features land in isolated modules with shared design tokens and testable services.
When should you invest in performance?
Before marketing spend — measure LCP, API p95, and error rates when traffic is still small so fixes are cheap.
Caching, image strategy, and database indexes are product decisions. Slow dashboards kill B2B trust as fast as consumer churn.