Mastering Web Typography: Building a Real-Time Font Preview Tool with the Local Font Access API.

We all know the struggle of choosing a font for a project. You have your design system in Figma, your VS Code open, and you're constantly switching back and forth to see if "Inter" really looks better than "Roboto" at 16px. Wouldn't it be great to just... preview them live, in the browser, alongside your actual content? In this post, I want to break down the core technical challenges I faced while building FontPreview.online and share the solutions that made it fast, accurate, and developer-friendly. The Core Challenge: A Million Fonts, One Page The first hurdle was loading and displaying over 1,000 Google Fonts without crashing the browser. The naive approach-loading every single font stylesheet at once-is a performance nightmare. The Solution: Lazy Loading with an Intersection Observer. We load the base UI, but the actual font files are only fetched when a card is about to scroll into view. // Simplified lazy loading setup const observer = new IntersectionObserver (( entries ) => { e