The latest articles on DEV Community by s971153 (@s971153). https://dev.to/s971153 https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F4034882%2Ffa8be155-2598-4fb8-a721-88e9c773d9b1.jpg https://dev.to/s971153 en s971153 Sat, 18 Jul 2026 07:22:41 +0000 https://dev.to/s971153/i-built-a-toolbox-where-your-files-never-leave-the-browser-10cb https://dev.to/s971153/i-built-a-toolbox-where-your-files-never-leave-the-browser-10cb <p>Every time I needed to convert a HEIC photo, compress a PDF, or format some JSON, I'd land on a site that made me upload my file to their server. For a screenshot, fine. For a contract or an ID scan? No thanks.</p> <p>So I built <a href="https://yunknow.cc/" rel="noopener noreferrer">Yunknow Toolbox</a> — free online tools where everything runs in your browser. Files are never uploaded. No account, no install.</p> <p>How it works (all client-side):</p> <ul> <li>Image convert &amp; compress (PNG/JPG/WebP/AVIF…) — Canvas API</li> <li>HEIC / TIFF decode — libheif / UTIF compiled to WebAssembly</li> <li>PDF merge / split / rotate / compress, image ↔ PDF — pdf-lib &amp; pdf.js</li> <li>JSON / Base64 / JWT / regex / QR / password / UUID — plain JS, no network</li> </ul> <p>Because nothing leaves your device, it's fast and private by design, and it works offline as a PWA. Built with Astro, multilingual (EN / 中文 / 日本語 / Deutsch), on Cloudflare Pages.</p> <p>If you've ever hesitated to paste sensitive data into an online tool, this is for you → <a href="https://yunknow.cc/" rel="noopener noreferrer">https://yunknow.cc/</a></p> <p>What tool should I add next?</p> webdev javascript privacy showdev