Most online PDF tools upload your files to a server and keep them there for hours. MoguanPDF runs all 24 tools — merge, split, compress, OCR, e-sign, watermark, convert to Word/Excel — 100% client-side with WebAssembly. Files never leave your device, it works offline as an installable PWA, and it's free with no account required.

The trickiest parts to build: local OCR with tesseract.js (English + Chinese) and PDF encryption with qpdf compiled to WASM. Happy to answer questions about the client-side architecture.