THE CWV CHECKLIST

Long checklists never get used. The Core Web Vitals checklist that wins is short enough that an engineer can run through it before pushing to production without thinking it is a chore. Mine has twelve items.

Sites that pass all twelve at launch rarely have CWV issues in production. Sites that skip three or four eventually fail at the 75th percentile and the team scrambles to fix it after Google has noticed.

1. Hero image is preloaded with link rel=preload as=image in the head.

2. Above-the-fold images have explicit width and height attributes, so layout reserves space before load.

3. WebP format, quality 82, resized to actual render dimensions before upload.

4. Critical CSS inlined in the head, rest deferred to async load.

5. Web fonts self-hosted with font-display: swap.

6. Initial JavaScript under 100KB on every public-facing page.

7. Analytics, marketing, and social-pixel scripts all deferred.

8. CSS Grid columns use minmax(0, 1fr) not 1fr to prevent overflow on long content.

9. Static rendering wherever the content allows.

10. Cloudflare or equivalent CDN in front of origin.

11. Field data measured weekly via Search Console > Core Web Vitals.

12. Build-time SEO linter fails the build on regressions.

Run through the list manually before any major launch. For ongoing engineering work, automate items 6, 8, 11, and 12 in CI; the rest are template-level checks that happen at design time and rarely regress.

When CWV regresses in production, the regression nearly always traces to one of these twelve items being silently violated. The diagnostic flow is: run through the list, find the violation, fix it, wait 28 days for CrUX to update, confirm.