Gunicorn 'Green Unicorn' is a Python WSGI HTTP Server for UNIX. It's a pre-fork worker model ported from Ruby's Unicorn project. The Gunicorn server is broadly compatible with various web frameworks, simply implemented, light on server resource usage, and fairly speedy.
New in v25: Per-app worker allocation for dirty arbiters, HTTP/2 support (beta)!
pip install gunicorn
gunicorn myapp:app --workers 4For ASGI applications (FastAPI, Starlette):
gunicorn myapp:app --worker-class asgi- WSGI support for Django, Flask, Pyramid, and any WSGI framework
- ASGI support (beta) for FastAPI, Starlette, Quart
- HTTP/2 support (beta) with multiplexed streams
- Dirty Arbiters for heavy workloads (ML models, long-running tasks)
- uWSGI binary protocol for nginx integration
- Multiple worker types: sync, gthread, gevent, eventlet, asgi
- Graceful worker process management
- Compatible with Python 3.9+
Full documentation at https://gunicorn.org
- Report bugs on GitHub Issues
- Chat in #gunicorn on Libera.chat
- See CONTRIBUTING.md for contribution guidelines
gunicorn has been serving Python web applications since 2010. If it's running in your production stack and saving your team time and money, please consider supporting its continued development:
Your sponsorship helps cover:
- Security updates and vulnerability responses
- Compatibility with new Python versions
- Bug fixes and performance improvements
- Documentation maintenance
Corporate sponsors: If gunicorn is part of your infrastructure, reach out for sponsored support options.
Gunicorn is released under the MIT License. See the LICENSE file for details.
