Website Speed Optimization Checklist
Measure before editing
Test representative pages on mobile and desktop. Distinguish lab results from real-user field data and record the conditions. Core Web Vitals cover loading, interaction responsiveness and visual stability; investigate the elements behind weak results rather than optimising only the score.
- Images: correct dimensions, modern formats and lazy loading for below-the-fold content.
- Main content: avoid making the key heading or image wait for unnecessary scripts.
- Scripts: remove unused third-party work and defer nonessential features.
- Fonts: reduce unnecessary files and check rendering behaviour.
- Layout: reserve space for media and avoid unexpected shifts.
Prioritise by impact
If a portfolio page downloads several multi-megabyte images, resizing and compressing those assets may matter more than a small stylesheet change. If the page appears quickly but freezes when a menu opens, inspect long-running work and interaction handling. Preserve image meaning and quality where customers need to inspect project details.
Verify the complete flow
Repeat the same measurement after a meaningful change and test navigation, forms and animations. Confirm that performance edits did not hide content, break accessibility or remove necessary measurement. Keep the result and conditions in the change record. Set a practical asset budget for future uploads so the next content update does not immediately recreate the same loading problem.