OpenSign — Free Self-Hosted Document Signing Platform

Introduction

OpenSign is an open-source electronic signature platform that provides a self-hosted alternative to DocuSign and Adobe Sign. It enables individuals and businesses to send documents for signature, track signing status, and maintain a secure audit trail without paying per-signature fees.

What OpenSign Does

• Sends PDF documents to one or multiple signers via email
• Captures legally binding electronic signatures with audit trails
• Supports signature fields, initials, dates, and text input placeholders
• Tracks document status in real time with completion notifications
• Stores signed documents with tamper-evident certificates

Architecture Overview

OpenSign is built with React on the frontend and Node.js on the backend, using MongoDB for document metadata and user management. PDF rendering and field placement happen client-side, while the backend handles email delivery, signing tokens, and audit log generation. The stack runs as multiple Docker containers orchestrated via Docker Compose.

Self-Hosting & Configuration

• Deploy using Docker Compose with the provided configuration
• Configure SMTP credentials for sending signature request emails
• Set up MongoDB for document and user storage
• Mount persistent volumes for uploaded and signed PDF files
• Customize branding with your organization logo and colors

Key Features

• Unlimited signatures with no per-document fees
• Multi-signer workflows with sequential or parallel signing
• Drag-and-drop field placement on PDF documents
• Completion certificates with timestamp and IP audit trails
• REST API for integrating signing into custom applications

Comparison with Similar Tools

• DocuSign — proprietary with per-envelope pricing; OpenSign is free and self-hosted
• DocuSeal — similar open-source e-sign; OpenSign uses MongoDB while DocuSeal uses PostgreSQL
• Documenso — open-source signing with a SaaS option; OpenSign is fully self-hosted
• SignRequest — cloud-based signing service; OpenSign keeps all documents on your infrastructure

FAQ

Q: Are OpenSign signatures legally binding? A: Yes, electronic signatures created with OpenSign comply with eIDAS and ESIGN Act requirements for standard electronic signatures.

Q: Can I use OpenSign without Docker? A: Yes, you can run the Node.js backend and React frontend directly, though Docker is the recommended deployment method.

Q: Does OpenSign support templates? A: Yes, you can create reusable document templates with pre-placed signature fields.

Q: How are signed documents secured? A: Each signed document includes a completion certificate with cryptographic hashes, timestamps, and signer IP addresses.

Sources

• https://github.com/OpenSignLabs/OpenSign
• https://opensignlabs.com