Why isn't your landing page converting? How speed (Lighthouse 100) and UX multiply your sales

Visitors decide in seconds

Someone arriving from an ad or from Google doesn't trust you yet. If the page stays blank, jumps while loading or stutters on mobile, they go back to the results and click a competitor. You paid for the click and lost the visit.

That's why I treat speed as part of the offer, not a technical detail. A lean landing page in static HTML can score 99–100 on Lighthouse, like this site.

The most common technical mistakes

• Page builders and off-the-shelf themes loading hundreds of KB of CSS and JavaScript the page doesn't use.
• A heavy hero image without dimensions or a modern format, delaying LCP.
• Pixels, chats and third-party widgets loading before the content.
• Too many fonts (and no preload), causing invisible text or layout shifts.

The UX mistakes that kill conversion

• A headline about the company instead of the customer's problem.
• The call-to-action button hidden below the fold on mobile.
• A long form with fields you don't need yet.
• No proof: real testimonials, verifiable numbers, the face of the person who will help.
• More than one goal on the same page, splitting attention.

How I build a landing page that sells

I start with the goal (a single action), write the message hierarchy and only then design. In code:

• Semantic HTML, lean CSS with Tailwind and JavaScript only where it adds value.
• AVIF/WebP images at the right sizes, with the main one at high priority.
• Local, subsetted fonts, no CDN dependency.
• Built-in technical SEO: titles, schema, sitemap and social metadata.
• A short form, validated and protected against spam.

Measure after launch

A landing page isn't done when it goes live. I follow field Core Web Vitals and the form's conversion rate, and adjust the headline, proof and call to action as the data shows.