uASGI: A High-Performance ASGI Web Server

uASGI is a lightweight and efficient ASGI (Asynchronous Server Gateway Interface) web server for Python, designed for speed and flexibility. It supports only HTTP/1.1 protocols, with built-in SSL/TLS capabilities and a multiprocessing worker model for handling concurrent requests.

Inspired by the need for a simple yet powerful ASGI server, uASGI aims to provide a solid foundation for deploying asynchronous Python web applications.

Features

• ASGI Specification Compliance: Fully compatible with ASGI 2.0 and 3.0 applications (HTTP and Lifespan).
• HTTP/1.1 Support: Robust handling of HTTP/1.1 requests using httptools.
• Multiprocessing Workers: Scale your application across multiple CPU cores with a configurable worker pool.
• Asynchronous I/O: Built on asyncio and optimized with uvloop for high concurrency.

Installation

uASGI requires Python 3.10 or later.

You can install uASGI and its dependencies using pip or uv

pip install uasgi
uv add uasgi

Usage

Running a Simple ASGI Application

Here's how you can run a basic FastAPI application with uASGI.

First, create an ASGI application in main.py

async def app(scope, receive, send):
    assert scope['type'] == 'http'

    await send({
        'type': 'http.response.start',
        'status': 200,
        'headers': [
            (b'content-type', b'text/plain'),
        ],
    })
    await send({
        'type': 'http.response.body',
        'body': b'Hello, world!',
    })

Then, run it from your terminal:

$ uasgi run main:app

Or you can run via gunicorn

$ gunicorn main:app --worker-class 'uasgi.UASGIWorker.UASGIWorker'

This will start the server on http://127.0.0.1:5000.

License

This project is licensed under the MIT License - see the LICENSE file for details.