HTTP3X

A WebSocket replacement built on HTTP/3 and QUIC.

Async Python server framework for HTTP/3 + WebTransport (QUIC).

What WebSocket would look like if it was designed today.

🚀 Quick Example

from http3x import App
from http3x.wt import Session

app = App()

class Echo(Session):
    async def on_stream(self, stream):
        async for data in stream:
            await stream.send(data)

app.wt.add("/echo", Echo)
app.run(host='::', port=4433, certfile="cert.pem", keyfile="key.pem")

Installation

pip install http3x

🚀 WebTransport Live Example

Streaming AI-style responses over HTTP/3 (WebTransport):

You: hello

AI:
h
he
hel
hell
hello 👋

This is NOT WebSocket.
This is native HTTP/3 streaming over QUIC.

See tests/wt_chat_stream.py and tests/wt_chat_stream.html for the complete example.

⚡ Why not WebSocket?

Feature	WebSocket	http3x
Protocol	TCP	QUIC (HTTP/3)
Streams	Single stream	Multiplexed streams
Datagram	No support	Built-in datagram
Head-of-line blocking	Yes	No

🚀 HTTP/3 Live Example

Simple HTTP/3 server with GET and POST endpoints:

from http3x import App
from http3x.h3 import Handler

app = App()

class ApiHandler(Handler):
    async def get(self):
        return {'status': 'ok'}
    
    async def post(self):
        return {'status': 'ok'}

app.h3.add('/h3', ApiHandler)

app.run(host='0.0.0.0', port=443, certfile="cert.pem", keyfile="key.pem")

Using curl with HTTP/3 support:

curl --http3-only -k https://localhost:443/h3
curl --http3-only -k -X POST -d "Hello, HTTP/3!" https://localhost:443/h3

See tests/h3_mini.py for the complete example.

Features

• HTTP/3 server (QUIC-based)
• WebTransport (stream + datagram)
• Multiplexed streams (no head-of-line blocking)
• Async/await API
• Built on aioquic

Documentation

• WebTransport Guide - Complete documentation for WebTransport functionality
• HTTP/3 Guide - Complete documentation for HTTP/3 functionality

More docs coming soon.

Project Links

• Source Code: GitHub Repository
• Documentation: Http3x Documentation
• PyPI: http3x
• Contributors: GitHub Contributors

Contributing

Contributions are welcome! Please visit the GitHub repository to contribute code, report issues, or suggest features.

License

This project is licensed under the Apache License 2.0. See the LICENSE file for details.