Signatron

A simple web application to sign PDF documents with image-based signatures.

Features

• Upload and view PDF documents
• Add signature images (PNG, JPG)
• Drag and drop signature positioning
• Resize signatures while maintaining aspect ratio
• Multi-page PDF support
• Download signed PDFs
• PDFs are never stored on the server: they stay in the browser and are only processed in memory when saving
• Signatures not saved to the library are deleted after 24 hours

Quick Start

Using Docker (Recommended)

docker compose up -d
# Open http://localhost:5000

Or with docker run:

docker build -t signatron .
docker run -p 5000:5000 signatron

Local Development

# Create virtual environment
python -m venv venv
source venv/bin/activate  # On Windows: venv\Scripts\activate

# Install dependencies
pip install -r requirements.txt

# Run the application
python app.py
# Open http://localhost:5000

Usage

1. Click "Open PDF" to upload a PDF document
2. Click "Add Signature" to upload a signature image (PNG/JPG)
3. Drag the signature to position it on the PDF
4. Use the corner handle to resize the signature
5. Click "Save PDF" to download the signed document

Project Structure

Signatron/
├── app.py              # Flask backend
├── templates/
│   └── index.html      # Web UI
├── static/
│   └── app.js          # Frontend logic
├── requirements.txt    # Python dependencies
├── Dockerfile
└── docker-compose.yml

Dependencies

• Flask - Web framework
• PyPDF - PDF reading/writing
• Pillow - Image processing
• ReportLab - PDF overlay generation
• Gunicorn - Production WSGI server

License

This project is licensed under the GNU General Public License v3.0 or later. See LICENSE for details.

Author

• oquinterol