vercel.json

{
    "devCommand":"uvicorn main:app --host 0.0.0.0 --port 3000",
    "builds": [
        {
            "src": "main.py",
            "use":"@vercel/python"
        }
    ],
    "routes":[
        {
            "src":"/(.*)",
            "dest":"main.py"
        }    
    ]
}