Hosting for FastAPI and Python APIs

What this page covers

• uvicorn / gunicorn
• PORT and 0.0.0.0
• requirements.txt
• health check
• webhook + logs + restart

How to deploy

1. ZIP or GitHub with requirements.txt / pyproject.toml and an entrypoint (uvicorn / gunicorn).
2. Set ENV (secrets, DATABASE_URL) — we configure PORT automatically.
3. Deploy → install deps → process listens on PORT → HTTPS URL + logs.

Minimal main.py

Add fastapi and uvicorn to requirements.txt for this example. /health checks the process response, not database or third-party API availability.

from fastapi import FastAPI

app = FastAPI()

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

Procfile and start command

main:app refers to the app object in main.py. Adjust the import path for a different structure. PORT comes from ENV; do not use --reload in production.

web: uvicorn main:app --host 0.0.0.0 --port $PORT

ENV you need

• PORT — your uvicorn/--port (or env) must use it.
• API keys, BOT_TOKEN, DATABASE_URL — dashboard secrets.
• CORS / ALLOWED_ORIGINS — if the frontend is on another domain.

Package managers and stack

• pip + requirements.txt
• Poetry / pip-tools — when the lockfile is clear to the builder

Common failures

• ModuleNotFoundError — deps missing from requirements or the environment was not reproduced.
• Connection refused / health check failed — the app is not listening on 0.0.0.0:$PORT.
• Crash on boot from ENV — Deploy Doctor flags missing keys before the build.

Pricing

Small API — Node Micro / similar plans from $3.29/mo. Heavier FastAPI / Mini App backends — MVP App at $13.08/mo.

Useful links

See also