Deploy a FastAPI app

Install FastAPI with its standard extras, which include the fastapi CLI and uvicorn:

fastapi[standard]

Then set the Start command to one of:

# app in main.py
fastapi run main.py --port $PORT

# app in app/main.py, two worker processes (Pro and above)
fastapi run app/main.py --port $PORT --workers 2

# plain uvicorn
uvicorn app.main:app --host 0.0.0.0 --port $PORT

Pin the Python version with a .python-version file. A Procfile web: line also works as the start command.

HTTPS ends at the platform's proxy, which forwards requests to your app over HTTP with an X-Forwarded-Proto header. Uvicorn only trusts that header from 127.0.0.1 by default, so redirects FastAPI generates (like the trailing-slash redirect from /items to /items/) point at http:// and browsers block them as mixed content.

Add the env var FORWARDED_ALLOW_IPS=*. Uvicorn and fastapi run both read it.

Every deploy requests your health check path (/ by default) and only goes live once it returns a 2xx or 3xx status. The platform keeps checking it after that. If / returns 404 or needs a login, add a route like /healthz that returns 200 and set it as the Health Check Path in Settings. Otherwise the deploy fails and the previous version keeps serving.

@app.get("/healthz", include_in_schema=False)
def healthz():
    return {"ok": True}

Add variables in the project's settings. They're available both while the app builds and while it runs, so build-time values (like framework-public keys) work without extra setup. See Environment variables. Read them with os.environ or pydantic-settings' BaseSettings. A .env file in the repo isn't needed in production.

Add a Postgres addon and DATABASE_URL is injected automatically. It uses the postgres:// scheme, which SQLAlchemy 2.x rejects, so rewrite it for the driver you use:

import os
from sqlalchemy.ext.asyncio import create_async_engine

url = os.environ["DATABASE_URL"].replace("postgres://", "postgresql+asyncpg://", 1)
engine = create_async_engine(url, pool_size=5)

Use postgresql+psycopg:// instead for a sync engine. Run Alembic migrations before the server starts:

alembic upgrade head && fastapi run main.py --port $PORT

FastAPI's BackgroundTasks run inside the same process and need nothing extra. For a queue (ARQ, Celery, Dramatiq), add a Redis addon and start the worker in the same container, for example arq app.worker.WorkerSettings & fastapi run main.py --port $PORT. Addons are private to their project, so a separate worker project can't reach them.

1. Sign in with GitHub and install the EthioDeploy app on the repo.
2. Click “New Project” and pick the repo.
3. Watch the build in the dashboard. When the health check passes, your app is live at <project-slug>.ethiodeploy.com. Every push to the default branch redeploys, and the old version keeps serving until the new one is healthy.