mmdGenerator

A simplified Mermaid diagram editor and exporter: edit .mmd files, preview live, and export to high-resolution PNG or PDF. Runs as a single Docker container (e.g. on Raspberry Pi 5) and is fully open source.

Features

• Code + preview: Split view with Mermaid code on the left and live diagram on the right
• Upload / save / download: Upload .mmd files, edit in the code panel, save to the server, or download as .mmd
• Export: Download the diagram as PNG (high resolution) or PDF
• Interactive diagram: Pan (drag) and zoom (mouse wheel) on the preview
• Diagram types and themes: Flowchart, sequence, class, Gantt, timeline, mindmap, pie, and more; multiple Mermaid themes
• i18n: German and English
• Dark / light mode: Default dark; theme applies to both UI and diagram
• Persistence: One diagram per .mmd; stored on the server

Quick start

With Docker (recommended)

docker build -t mmdgenerator .
docker run -d -p 8000:8000 \
  -v mmd-data:/data -v mmd-logs:/logs \
  -e MMD_DATA_DIR=/data -e LOG_DIR=/logs \
  mmdgenerator

Open http://localhost:8000

With docker-compose

docker-compose up -d

Deploy on Raspberry Pi

Use the pre-built arm64 image (no build on the Pi). See Deployment → Deploy on Raspberry Pi for one-command options (docker run, docker compose -f docker-compose.raspberry-pi.yml up -d, or the deploy script).

Local development

Backend

cd backend
python -m venv .venv
.venv/bin/pip install -r requirements.txt
# Install system Cairo (e.g. Ubuntu: sudo apt install libcairo2 libpango-1.0-0 libpangocairo-1.0-0)
.venv/bin/uvicorn app.main:app --reload --port 8000

Frontend

cd frontend
npm install
npm run dev

Frontend dev server proxies /api to the backend. Open http://localhost:5173

Documentation

• Architecture
• Development
• Deployment

License

This project is licensed under the Apache License 2.0.

Contributing

See CONTRIBUTING.md. Please update documentation when you change behavior or setup.