Qwen-Reverse

Reverse-engineered async Python client for chat.qwen.ai — text chat, streaming with real-time reasoning, tool calling, image and video generation. No official API key required (works anonymously).

pip install qwen-reverse

Features

• Chat — one-shot, streaming (SSE incremental), multi-turn with conversation memory (conversation_id / parent_id chaining)
• Real-time reasoning — reasoning events streamed token-by-token before the answer, in both plain and multi-turn mode
• Tool calling — OpenAI-style function definitions; either let the SDK execute them (JSON-stringified follow-up) or handle them yourself with emit_tool_calls=True
• Vision — image upload + chat about it
• Image / video generation — t2i and t2v returning CDN URLs (cdn.qwenlm.ai)
• No account required — the web API works without a token; OAuth device-flow login (chat.qwen.ai account) is also implemented
• Optional FastAPI server — OpenAI-compatible /v1/chat/completions and /v1/models (see server/)

Quickstart

import asyncio
from qwen_reverse import Generative

async def main():
    gen = Generative()
    print(await gen.generate("Explain what a kernel is in 2 lines"))

asyncio.run(main())

Streaming with real-time thinking

import asyncio
from qwen_reverse import Generative

async def main():
    gen = Generative()
    async for event in gen.stream("Explain in 2 sentences what an OS kernel is"):
        if event["type"] == "reasoning":
            print(f"\r\033[90m{event['data']}\033[0m", end="", flush=True)
        elif event["type"] == "content":
            print(event["data"], end="", flush=True)

asyncio.run(main())

Multi-turn conversation

import asyncio
from qwen_reverse import Conversation

async def main():
    conv = Conversation()
    r1 = await conv.send("My name is Popbob and I work with kernels in C.")
    r2 = await conv.send("What is my name?")  # remembers turn 1
    print(r2)  # "Popbob"
    print(conv.conversation_id, conv.parent_id)

asyncio.run(main())

Tool calling (automatic execution)

import asyncio
from qwen_reverse import Conversation

WEATHER_TOOL = {
    "type": "function",
    "function": {
        "name": "get_weather",
        "description": "Get current weather for a city",
        "parameters": {
            "type": "object",
            "properties": {"city": {"type": "string"}},
            "required": ["city"],
        },
    },
}

async def main():
    conv = Conversation(tools=[WEATHER_TOOL])
    async for event in conv.stream("What's the weather in Buenos Aires?"):
        if event["type"] == "tool_calls":
            print("[tool_calls]", event["data"])
        elif event["type"] == "content":
            print(event["data"], end="", flush=True)

asyncio.run(main())

For raw tool-call JSON instead of execution, pass emit_tool_calls=True to stream()/create_chat().

Image generation

import asyncio
from qwen_reverse import Image

async def main():
    img = Image()
    urls = await img.generate(
        "A cyberpunk dragon flying over a neon city, anime style",
        aspect_ratio="16:9",
    )
    print(urls[0])  # https://cdn.qwenlm.ai/output/...

asyncio.run(main())

API

Events emitted by stream()

Authentication

Anonymous mode works — no token required for most features (lower rate limits). For higher limits, log in with a chat.qwen.ai account:

import asyncio
from qwen_reverse import start_device_login, complete_device_login

async def main():
    client, data = await start_device_login()
    print(data["verification_uri_complete"])  # open in a logged-in browser
    # after authorizing:
    token = await complete_device_login(client, data)
    print(token)

Models

Defaults to qwen3.8-max. Others: qwen3.7-plus, qwen3.7-max, plus vision / image / video models — see qwen_reverse/models.py and fetch_models().

Running the tests

pip install -e ".[dev]"
pytest

Optional server (OpenAI-compatible)

pip install "qwen-reverse[server]"
cd server
uvicorn app.main:app --port 8000
# GET  /v1/models
# POST /v1/chat/completions  (OpenAI-style, streaming SSE)

How it works

The client replicates what the official web app does against chat.qwen.ai:

1. Create a chat via POST /api/v2/chats/new (gets a chat_id)
2. Stream the response via POST /api/v2/chat/completions?chat_id=... with version: 2.1, incremental_output and a feature_config that enables the reasoning stream
3. Multi-turn chaining uses the server's response_id (assistant message fid) as the next turn's parent_id
4. Anti-bot headers are regenerated per request: ssxmod_itna cookies (custom LZW + custom base64), bx-umidtoken, fingerprint

Disclaimer

This project is for educational and research purposes. It is not affiliated with or endorsed by Alibaba/Qwen. Use at your own risk — the endpoints may change or the service may rate-limit or block unofficial clients. MIT licensed; reverse-engineering references based on g4f (MIT).