Building a 100% Client-Side PDF Editor: Why I Chose Astro and WebAssembly

The Privacy Problem with Online PDF Tools We’ve all been there: you need to merge two PDFs or edit a quick detail, so you Google "PDF editor." You find a dozen sites, upload your sensitive document (maybe an invoice or a contract), and hope for the best. As a developer, this always felt like a massive privacy hole. Why should my data live on someone else's server just to perform a simple merge operation? That’s why I decided to build DumPDF —a tool that does everything strictly in the browser. No uploads, no servers, just your files and your CPU. The Architecture: Why Astro + TypeScript? When building a tool that needs to be fast and SEO-friendly, I chose Astro. Astro's "islands" architecture is perfect here. Since the PDF manipulation happens entirely on the client side, I didn't need a heavy backend. I used Astro to ship zero-JavaScript by default for the landing pages, only loading the heavy libraries (like pdf-lib and tesseract.js) when the user actually starts an "action." Key dep