SignIO lets you instantly annotate PDFs from your computer on your tablet using your stylus—while the file stays securely on your Windows PC.
No installs on your tablet. No cloud. Just open your browser and go.
Imagine you're working on your PC and want to mark up a PDF using your tablet and stylus. SignIO makes that super easy:
- 🖋️ Annotate with your stylus on iPad, Android tablets, or even phones
- 🖥️ Runs on your Windows PC
- 🌐 Access it from your tablet browser
- 🔐 Files never leave your computer
- 🆓 100% Free and open source
- Download and launch SignIO on your Windows PC
- A local web address will appear
- Open that link in your tablet’s browser (make sure both devices are on the same Wi-Fi)
- Start annotating with your stylus!
No accounts. No sync. No setup headaches.
(Insert a short GIF or video here showing the workflow, coming soon) Select a PDF → Grab your tablet → Annotate smoothly in your browser → Save or Open the annotated file on your computer
👉 Get the latest version on GitHub
Does it work on iPad or Android tablets? Yes! If it has a browser and a stylus, it works.
Is anything uploaded to the internet? No. Your PDFs never leave your device.
Can I use this offline? Yes, as long as your PC and tablet are connected to the same Wi-Fi or hotspot.
- Undo/Redo
- History
- Native iOS version (€1, planned)
If you like SignIO and want to support future features:
Or simply ⭐ star it on GitHub
MIT License · Made with 💻 + ✍️