API / Developer Tool checklist before you ship

Performance

0/5

Core Web Vitals targets set (LCP < 2.5s, CLS < 0.1, INP < 200ms)

Critical

Images optimized (WebP/AVIF, correct sizes, lazy loading)

Critical

JavaScript bundle size minimized

Important

Server-side rendering or static generation for public pages

Important

CDN configured for static assets

Important

0/5

Analytics tool configured (Posthog, Mixpanel, Segment, or GA4)

Critical

Error monitoring in place (Sentry or similar)

Critical

Key business events tracked (signup, conversion, churn)

Critical

Uptime monitoring configured

Important

Analytics dashboard for key metrics

Important

0/4

Unit test coverage ≥ 70% for business logic

Important

End-to-end tests for critical user journeys

Critical

Tests run in CI on every PR

Critical

Cross-browser and cross-device testing

Important