The problem
Getting a document signed should take minutes, but it often means printing, scanning and chasing people by email, with no clear record of who signed what and when. SignPro handles the whole loop in one place: upload the document, send it out, collect signatures and keep evidence of each signing.
What SignPro does
- Upload PDF or Word (DOCX) documents of up to 25 MB and 500 pages; the app parses the pages for preview.
- Send a signature request to one or more recipients by email or SMS, with a personal message and the signature spot marked on the page.
- Recipients open a public signing page, draw their signature, accept the consent statement and submit, without creating an account.
- Every signing is sealed with an evidence hash and recorded by an audit service.
- A dashboard lists every document with its status, so senders can see what is pending, signed, declined or void.
- Senders can connect their own SMTP server, so signing emails come from their own domain.
- A companion Chrome extension (Manifest V3) checks for pending signature requests and shows a desktop notification with a "Sign Now" button.
Tools used
The frontend is React 18 with Vite and React Router. The API is Node.js with Express, backed by PostgreSQL and S3-compatible object storage (Cloudflare R2 through the AWS SDK). PDF and DOCX handling uses pdf-lib, PDF.js and Mammoth. Email goes out through Nodemailer and SMS through Twilio. Authentication uses JWT sessions and bcrypt password hashing, with Helmet and rate limiting on the API. The whole stack runs with Docker Compose and is tested with Jest, Supertest and Puppeteer.
How I built it
I built SignPro with AI-assisted development, using Claude Code as a pair programmer. The work followed the real user journey screen by screen: login, dashboard, upload, document detail and the public signing page. Because the product handles legal documents, the security pieces are written in explicitly: hashed passwords, signed session tokens, API rate limiting and an audit trail. I also produced a design system for the app that documents its current look and a second, editorial "Luxe" direction for premium surfaces.
Result
SignPro covers the whole signing loop end to end. A sender uploads a document, sends it by email or SMS and gets it back signed, while the recipient signs from a link without creating an account. Every signature is backed by an evidence hash and an audit record, the dashboard shows where each document stands, and the API and signing flow are covered by automated tests with Jest, Supertest and Puppeteer.
SignPro runs as a live demo, and its full source code is public on GitHub, so you can try the signing flow and read how it works.
