I built a toolbox where your files never leave the browser

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. So I built Yunknow Toolbox — free online tools where everything runs in your browser. Files are never uploaded. No account, no install. How it works (all client-side): Image convert & compress (PNG/JPG/WebP/AVIF…) — Canvas API HEIC / TIFF decode — libheif / UTIF compiled to WebAssembly PDF merge / split / rotate / compress, image ↔ PDF — pdf-lib & pdf.js JSON / Base64 / JWT / regex / QR / password / UUID — plain JS, no network 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. If you've ever hesitated to paste sensitive data into an online tool, this is for you → https://yunknow.cc/ What tool should I add next?