A fully offline document signing system. React + Electron runs on a PC as host. iPads connect over the local network — no internet required. Documents are signed on iPad, the signed copy is automatically emailed. Zero SaaS fees, zero monthly cost, completely self-contained.
SaaS signing tools charge per signature or per seat. This system eliminates that entirely by running the whole signing workflow on a local network. The Electron host serves documents to iPads over the local IP. Clients sign with Apple Pencil or finger. The signed PDF is generated instantly and emailed — all without touching the internet.
The Electron app spins up a local Express server on boot. iPads navigate to the host's IP — the PWA loads and connects. Signatures are captured on the Canvas API, merged into the PDF server-side, and dispatched via SMTP in under 3 seconds.
Embedding a hand-drawn canvas signature into an existing PDF at the correct position, preserving document integrity and producing a legally presentable output.
No mDNS — iPads needed a simple way to find the host. Solved with a one-time QR code displayed by Electron encoding the local IP and port.
If SMTP fails, signed PDFs are queued locally and retried automatically when connectivity is restored, ensuring no signed document is lost.
Multiple iPads signing simultaneously needed document state and signing status to sync across devices without conflicts or duplicate entries.