Deploy a Python FastAPI App with OpenClaw

FastAPI is the best Python framework for AI backends. It has native async support, automatic OpenAPI docs, and Pydantic validation.

The FastAPI App

# main.py
from fastapi import FastAPI, HTTPException
from pydantic import BaseModel
from contextlib import asynccontextmanager

@asynccontextmanager
async def lifespan(app: FastAPI):
    # Startup
    openclaw.init()
    yield
    # Shutdown
    openclaw.close()

app = FastAPI(lifespan=lifespan)

class ChatRequest(BaseModel):
    message: str
    userId: str | None = None

@app.get('/health')
async def health():
    return {'status': 'ok'}

@app.post('/chat')
async def chat(req: ChatRequest):
    response = await openclaw.chat(req.message, user_id=req.userId)
    return {'response': response}

Run

uvicorn main:app --host 0.0.0.0 --port 3000

Deploy

fly launch --no-deploy
fly secrets set OPENAI_API_KEY=sk-...
fly deploy

API Docs

FastAPI automatically generates OpenAPI docs at /docs. Swagger UI at /docs, ReDoc at /redoc.