---
title: "How to deploy a FastAPI app"
description: "Deploy a FastAPI app to Ample with your coding agent, the CLI or MCP, using build and start commands verified on September 20, 2026."
canonical_url: "https://ample.computer/guides/fastapi"
last_updated: "2026-09-20"
author: "Ample Computer"
---

# How to deploy a FastAPI app

Deploy a FastAPI app to Ample with your coding agent, the CLI or MCP, using build and start commands verified on September 20, 2026.

## The short version

To deploy a FastAPI app on Ample, run `ample deploy . --name <app-name> --public --start "python3 run.py"` in the project directory, or ask your coding agent to deploy it to Ample. Ample builds it on the `python-3.12` template, starts it with `python3 run.py` and returns a public HTTPS URL. Python start commands are not inferred, so the command passes `--start`.

## Deploy FastAPI

1. **Ask your coding agent.** Install the Ample CLI and create an account, then ask your agent: "Deploy this FastAPI app to Ample".

   ```sh
   curl -fsSL https://get.ample.computer/install.sh | sh
   ample auth signup
   ```

2. **Or deploy from the CLI.** It waits until the app is live or failed and prints the URL.

   ```sh
   ample deploy . --name <app-name> --public --start "python3 run.py"
   ```

3. **Or use MCP.** Call `ample_deploy` on `https://api.ample.computer/mcp` (or `ample mcp` over stdio).
4. **Verify.** On failure read `ample logs <deployment_id> --kind build`, fix the cause and deploy again.

## Tested configuration

| | |
|---|---|
| Template | `python-3.12` |
| Install | `python3 -m pip install --target .ample/python -r requirements.txt` |
| Start | `PYTHONPATH=.ample/python:${PYTHONPATH:-} python3 run.py` |
| Tested size | `s-1vcpu-1gb` |

Start uvicorn from a small run.py that reads PORT; pass --start "python3 run.py" because Python start commands are not inferred. Ample detects the runtime, installs dependencies, runs the build when present and starts the app on the python-3.12 template behind a public HTTPS URL.

Last verification (2026-09-20): FastAPI app installed with pip into .ample/python and started with uvicorn on python-3.12; / and /health served correctly.

## You need

- A requirements.txt (or pyproject) and a start command that reads PORT and binds 0.0.0.0
- An Ample account token with servers:write

## Know the limits

- Verified on the python-3.12 template at s-1vcpu-1gb; other templates and sizes are not verified by this recipe.
- Dependencies install with pip into .ample/python from requirements.txt; pyproject-only projects use uv when available.

## Move a FastAPI app to Ample

- [How to move a FastAPI app from AWS EC2 to Ample](https://ample.computer/migrate/aws-ec2-app/fastapi)
- [How to move a FastAPI app from DigitalOcean Droplet to Ample](https://ample.computer/migrate/digitalocean-droplet-app/fastapi)
- [How to move a FastAPI app from Fly.io to Ample](https://ample.computer/migrate/fly-io-app/fastapi)
- [How to move a FastAPI app from Heroku to Ample](https://ample.computer/migrate/heroku-app/fastapi)
- [How to move a FastAPI app from Netlify to Ample](https://ample.computer/migrate/netlify-web-app/fastapi)
- [How to move a FastAPI app from Railway to Ample](https://ample.computer/migrate/railway-app/fastapi)
- [How to move a FastAPI app from Render web service to Ample](https://ample.computer/migrate/render-web-service/fastapi)
- [How to move a FastAPI app from Vercel to Ample](https://ample.computer/migrate/vercel-app/fastapi)

## Frequently asked questions

### Do I need a Dockerfile to deploy FastAPI?

No. Ample detects FastAPI from the repository and builds it from source on the `python-3.12` template. Dockerfile build steps are not run.

### How do I add a database to a FastAPI app?

Leave DATABASE_URL unset and deploy: when the code needs Postgres, MySQL, Redis or MongoDB, Ample creates a managed database and passes its connection string to the app. See [Connect Postgres for FastAPI](https://ample.computer/guides/fastapi/database-connection).

### What does it cost to host a FastAPI app on Ample?

The Free plan runs 2 apps at once with no card and a hard monthly budget, so it never bills you. Larger needs are priced on volume; see [pricing](https://ample.computer/pricing).

### What if the deploy fails?

`ample deploy` waits until the app is live or failed. A failure returns who must act, a diagnosis and a suggested fix; read the logs with `ample logs <deployment_id> --kind build`. See [Diagnose deployment failures for FastAPI](https://ample.computer/guides/fastapi/deployment-diagnostics).

## More for FastAPI

- [How to serve FastAPI public assets through a CDN on Ample](https://ample.computer/guides/fastapi/cdn-assets): Cdn assets for a FastAPI app on Ample
- [How to set environment variables and secrets for a FastAPI app on Ample](https://ample.computer/guides/fastapi/configuration-secrets): Configure environment variables and secrets for a FastAPI app on Ample
- [How to connect a FastAPI app to Postgres on Ample](https://ample.computer/guides/fastapi/database-connection): Connect a FastAPI app to PostgreSQL on Ample
- [How to fix a failed FastAPI deploy on Ample](https://ample.computer/guides/fastapi/deployment-diagnostics): Deployment diagnostics for a FastAPI app on Ample
- [How to use S3-compatible storage from a FastAPI app on Ample](https://ample.computer/guides/fastapi/object-client): Configure S3-compatible access for a FastAPI app on Ample
- [How to serve private files from a FastAPI app on Ample](https://ample.computer/guides/fastapi/private-file-access): Private file access for a FastAPI app on Ample
- [How to run database migrations for a FastAPI app on Ample](https://ample.computer/guides/fastapi/schema-changes): Apply database schema changes for a FastAPI app on Ample with a release command