Next.js + FastAPI + Bindings

// vercel.json
{
  "services": {
    "frontend": {
      "root": "frontend/",
      "framework": "nextjs",
      "bindings": [
        {
          "type": "service",
          "service": "backend",
          "format": "url",
          "env": "BACKEND_URL"
        }
      ]
    },
    "backend": {
      "root": "backend/",
      "entrypoint": "main:app"
    }
  },
  "rewrites": [
    { "source": "/(.*)", "destination": { "service": "frontend" } }
  ]
}