Pre-launch checklist: performance, responsiveness, protection

Launch day is too late to discover the mobile menu overlaps the logo. This is the pass we run on every build, in this order, the week before it goes live.

1. Performance (target: Lighthouse 95+ on mobile)

• Images: every raster served as AVIF or WebP with a srcset; hero image preloaded; nothing above 300 KB.
• Fonts: only the weights in use, self-hosted, with font-display swap.
• Scripts: deferred, no third-party tag that is not earning its place. Analytics loads after interaction.
• Layout shift: fixed aspect ratios on every image and embed. A shifting page feels broken even when it is fast.

2. Responsiveness (a walk, not a resize)

We do not shrink the desktop layout. Each breakpoint gets its own decisions: what the headline size is at 390 px, whether a grid becomes a list, where the call to action sits when the thumb rests. Then we check the four widths that matter: 1440, 1024, 768 and 390, plus one ugly one in between.

3. Accessibility that costs nothing

Real heading order, alt text that describes, focus states you can see, and every animation behind prefers-reduced-motion. This is not compliance theatre; it is what makes the site usable on a bright beach with one hand.

4. Protection

For launch sites that carry a client's renders before the public announcement, we ship an obfuscated build, strip source maps, watermark preview environments and gate the staging URL. Nothing stops a determined copy, but nothing should make it trivial either.

5. The last hour

Favicons and social cards, 404 that matches the brand, forms tested with a real inbox, redirects from the old site, and a backup of the previous version you can restore in five minutes. Then publish, and watch the first hundred visits with the analytics open.