🦄 Tsuno

High-performance WSGI/ASGI server powered by Rust

Tsuno aims to be a drop-in replacement for Gunicorn and Uvicorn with a Rust-powered transport layer. Run your Django, Flask, FastAPI, Starlette, and connect-python applications with HTTP/2 support.

Installation

pip install tsuno

Quick Start

Command Line

tsuno myapp:app --workers 4 --bind 0.0.0.0:8000

Python API

Flask (WSGI):

from flask import Flask
from tsuno import run

app = Flask(__name__)

@app.route("/")
def hello():
    return "Hello World"

if __name__ == "__main__":
    run(app)

FastAPI (ASGI):

from fastapi import FastAPI
from tsuno import run

app = FastAPI()

@app.get("/")
async def root():
    return {"message": "Hello World"}

if __name__ == "__main__":
    run(app)

See examples/ for complete working examples.

What Makes Tsuno Different

• Mixed Protocol Serving: Serve WSGI and ASGI apps simultaneously on the same server (example)
• High Performance: Powered by Tokio and hyper
• API Compatibility: Aims for complete compatibility with both Gunicorn and Uvicorn APIs
• Unix Domain Sockets: Full UDS support for nginx integration (example)

Examples

Complete working examples in the examples/ directory:

Configuration

Command Line

# Basic
tsuno myapp:app --bind 0.0.0.0:8000 --workers 4

# With auto-reload (development)
tsuno myapp:app --reload

# With Unix domain socket
tsuno myapp:app --uds /tmp/tsuno.sock

# With configuration file
tsuno myapp:app -c tsuno.toml

Configuration File

Python format (Gunicorn-compatible):

# tsuno.conf.py
bind = "0.0.0.0:8000"
workers = 4
threads = 2
log_level = "info"

TOML format:

# tsuno.toml
bind = "0.0.0.0:8000"
workers = 4
threads = 2
log_level = "info"

See examples/tsuno.toml for all options.

Python API

from tsuno import run

run(
    app,
    host="0.0.0.0",
    port=8000,
    workers=4,
    reload=True,  # Development only
)

Production Features

Worker Management

• Auto-restart crashed workers
• Graceful shutdown and reload
• Worker timeout monitoring
• Max requests per worker (memory leak prevention)

Graceful Reload (Zero-Downtime)

# Start with PID file
tsuno myapp:app --pid /var/run/tsuno.pid

# Graceful reload (no downtime)
kill -HUP $(cat /var/run/tsuno.pid)

Logging

• Structured logging (text/JSON)
• Access log support
• Customizable log formats

Performance

Performance varies by workload, platform, and configuration. Run wrk or h2load benchmarks to measure performance on your specific hardware.

Migration

From Gunicorn

# Before
gunicorn myapp:app --workers 4 --bind 0.0.0.0:8000

# After (same syntax!)
tsuno myapp:app --workers 4 --bind 0.0.0.0:8000

From Uvicorn

# Before
import uvicorn
uvicorn.run(app, host="0.0.0.0", port=8000, workers=4)

# After (compatible API!)
import tsuno
tsuno.run(app, host="0.0.0.0", port=8000, workers=4)

Development Status

Tsuno is in early development (alpha stage).

• ⚠️ Real-world production testing needed

Help us test! Report issues at github.com/i2y/tsuno/issues

Requirements

• Python 3.11-3.14
• Rust toolchain (for building from source)

Platform Support

• macOS: Fully supported
• Linux: Fully supported
• Windows: Not tested yet

Known Limitations

Project Status: Alpha - production testing needed

Not Implemented Yet:

• SSL/TLS support
• CLI daemon mode (Python API supports it via daemon=True)
• Custom worker_connections limits
• Error log file redirection

Contributing

Contributions are welcome! Please:

• Report issues at github.com/i2y/tsuno/issues
• Submit pull requests for bug fixes or new features
• Help improve documentation and examples

License

MIT License - see LICENSE

Links

• Repository: github.com/i2y/tsuno
• Issues: github.com/i2y/tsuno/issues

Acknowledgments

Tsuno is inspired by and builds upon excellent work from:

• Gunicorn & Uvicorn: Server standards
• Granian: Rust-Python hybrid architecture
• Tokio, hyper, PyO3: Rust ecosystem