Universal Signatures

Draw or type a signature and sign PDFs entirely in your browser — free, open source, documents never leave your device. Optionally save a verified signature to the cloud with a Universal ID. Part of the Universal Apps family from UNI·SIM.

Live at opensource.unisim.co.uk/signatures.

Features

• Create a signature — draw with mouse/touch/stylus, or type your name in a cursive font (rasterised to PNG).
• Sign a PDF — upload a PDF, pick the page, position and size, and download the signed copy. 100% client-side via pdf-lib; the document is never uploaded.
• Save a verified signature to the cloud (optional, gated) — store your signature against your Universal ID with a SHA-256 hash + a public certificate link anyone can verify.

Free vs. cloud

Signing PDFs is free forever and needs no account. Saving a verified signature to our cloud is a hosted feature — it requires a Universal ID plus a token, an active project, or a subscription, because hosting costs money. Don't want to pay? Self-host the whole thing for free (see below).

Stack

Vite 6 · React 18 · TypeScript · Tailwind v4 · zustand · pdf-lib · @unisim/sdk (shared navbar, SSO + entitlements).

Develop

cd /Users/jamesmarkey/Github/UNISIM/Universal_Apps/Universal_Signatures
npm install
npm run dev -- --port 5186

npm run build runs tsc -b && vite build (strict TypeScript). Output is a static dist/ served by Cloudflare Pages under /signatures/.

Each build bakes the commit SHA into a <meta name="build-sha"> tag and logs build: <sha> to the console at startup, so you can tell which build is live in-browser. On Cloudflare Pages the SHA comes from CF_PAGES_COMMIT_SHA; locally it falls back to the git short SHA (or dev).

Offline "dummy account"

In local dev the app runs against an offline mock of the Universal ID by default — no network, no real Supabase. Open the profile menu → Sign in and use the demo credentials:

james@unisim.co.uk / KyJam91

You'll get a seeded signed-in world (owner of a demo org with one free token) so the navbar profile, cloud save and verify pages all work offline. To test against the real Supabase project instead, set VITE_REAL_AUTH=1 in .env.local. The mock lives in @unisim/sdk (mockAuth) and is hard-guarded off in production.

Self-hosting

Universal Signatures is MIT-licensed and self-contained. To run your own copy — including cloud save against your own Supabase, with no entitlement gate:

1. Clone this repo and npm install.
2. Create a Supabase project and apply the signatures table + the verify_signature_cert RPC (see 0028_signatures.sql in the platform repo, or the SQL in docs/).
3. Set VITE_PLATFORM_SUPABASE_URL / VITE_PLATFORM_SUPABASE_ANON_KEY to your project in .env.local.
4. Relax or remove the entitlement check in src/lib/cloud.ts (useCloudGate) so cloud save is available to all your signed-in users.
5. npm run build and host dist/ anywhere static (Cloudflare Pages, Netlify, nginx, …).

That's it — you get the full app, cloud save included, for the cost of your own hosting.

Privacy

PDFs are parsed and signed locally and never uploaded. Only the optional "save verified signature" feature sends data (your signature image + hash) to the cloud, and only when you're signed in and choose to.