Summary
Fast pages begin with measurement. Reduce unnecessary work, optimize the assets visitors see first, and test on real devices and networks to keep the experience responsive.
1. Measure the experience
Use browser performance tools and real-user data to understand where visitors wait. Look at loading, responsiveness, and layout stability together: a page that appears quickly but shifts or ignores input can still feel slow.
Test representative pages on a mobile device and a constrained connection. Record a baseline before making changes so you can compare the results.
2. Prioritize critical assets
Size images for their display area, compress them, and choose suitable formats. Reserve image dimensions to reduce layout shifts. Load below-the-fold images lazily, but allow the main visible image to load promptly.
Keep styles needed for the first view accessible, and remove scripts and fonts the page does not use. Delay nonessential third-party code when it does not need to run immediately.
3. Keep pages fast over time
Cache reusable assets appropriately and avoid sending more JavaScript than the interaction needs. Break up long tasks when they block the main thread, and check how changes affect slower devices.
Set performance budgets for important pages and revisit measurements after releases. Small regressions are easier to fix when caught early.