A practical checklist for improving Core Web Vitals, route transitions, and API throughput in modern Next.js applications.
Start With What Users Feel
Performance work should start from user journeys, not generic audits. Measure page load, first interaction, and route transitions on your most-used screens.
Teams usually gain more by fixing three slow templates than by touching every route at once.
Build a Repeatable Optimization Loop
Treat optimization as a weekly loop: measure, prioritize, fix, and verify. Keep the same dashboards so regressions are visible immediately.
- Ship compressed responsive images with accurate `sizes`.
- Avoid waterfall fetches on server components.
- Split expensive client bundles by route intent.
- Cache API responses at the edge where possible.
Protect Performance in CI
Once you improve metrics, lock them with budgets. Performance should fail builds the same way tests fail builds.
This keeps fast experiences from being undone during feature rush cycles.