No Dockerfile
The platform detects FastAPI from requirements.txt / pyproject.toml, picks the build and start commands, and lists the environment variables your code reads.
FastAPI deploy guide · Agent Lab Deploy
Deploy FastAPI
in one sentence.
Upload your FastAPI project as it is — no Dockerfile — or tell Claude Code, Codex or Cursor "deploy this". Agent Lab builds it into a web service, gives every version a preview URL with rollback, and checks uploads for leaked keys. Apps and databases run on Google Cloud in Taiwan.
> deploy this FastAPI app
sites_createmy-fastapi
sites_deployFastAPI detected
sites_deploy_statusbuilt · secret scan passed
Live at my-fastapi--acme.hosting.agentlab.run
Why deploy FastAPI on Agent Lab
FastAPI online without running a server yourself
Python project, built from source with no Dockerfile, deployed as a web service.
Preview, go live, roll back
Every upload is a new version with its own URL. Look first, then go live; switch back to any version in one click.
Leaked keys caught
Uploads are checked for API keys and credentials before they can go live. Secrets go in the console, never in the code.
PostgreSQL in one click
Create a database and connect it; the connection is written into the app's environment and the password is never shown.
Your options
FastAPI on Agent Lab, or on your own VPS
Scroll the table sideways.
| What you care about | Agent Lab Deploy | Your own VPS |
|---|---|---|
| Setup | Upload or say one sentence; no Dockerfile | SSH, a runtime, a process manager, a reverse proxy |
| HTTPS and domains | Automatic, custom domains on paid plans | Certbot and DNS by hand |
| Preview and rollback | Every version has its own URL; roll back in one click | Write your own scripts |
| Before going live | Uploads checked for leaked keys | Nothing unless you set it up |
| Database | PostgreSQL in one click, connection written into the app | Install and back it up yourself |
| Cost to start | Free plan: NT$0, one size-S app (sleeps when idle) | A VPS at roughly NT$200–600 a month, plus your time |
Steps
Deploy FastAPI in four steps
Prepare
Keep requirements.txt / pyproject.toml at the top of the project and commit the lockfile. Leave out node_modules, .git, dist and .env.
Upload or ask
Drop the folder on a project's Deploy tab, push from GitHub, or ask your AI tool through Agent Lab MCP.
Build and check
The platform builds the version and checks it for leaked keys. Enter any secrets it lists in Settings.
Preview and go live
The first version goes live once it builds. Later ones get a preview URL; go live when you're happy.
Setup
What Agent Lab runs for FastAPI
FastAPI is a common choice for AI backends and MCP servers: an always-on service at a fixed address that an AI tool deploys in one sentence. If the entry point isn't app in main.py, add a Procfile: web: uvicorn mypkg.api:app --host 0.0.0.0 --port $PORT. The /docs Swagger UI is public by default; make the project private with a password if it shouldn't be.
Build and start
# Agent Lab 偵測到 FastAPI 後自動產生 ASGI 伺服器指令
# Agent Lab detects FastAPI and generates the ASGI server command
pip install -r requirements.txt # 也支援 Poetry、uv
# 用 uvicorn 啟動，監聽 0.0.0.0:$PORT（預設 8080）DATABASE_URLwritten for you when you connect an Agent Lab PostgreSQL.OPENAI_API_KEYthird-party keys like this go under Secrets; only you know the value.
Or ask your AI tool
Read https://app.agentlab.cresclab.com/agent/deploy.md and deploy this FastAPI project to Agent Lab. Show me the build plan and the environment variables it needs first, tell me where to enter any secrets, and wait for my OK before it goes live.FAQ
Deploying FastAPI: questions
Do I need a Dockerfile to deploy FastAPI?
No. Upload the FastAPI project with requirements.txt / pyproject.toml at the top and Agent Lab detects the framework, builds it and starts it. A Dockerfile at the top, if there is one, is used instead. Docs →
Which Python version does FastAPI run on?
It reads .python-version, then the version constraint in pyproject, and falls back to 3.12; 3.10 to 3.14 are supported. ALPACK_PYTHON_VERSION sets one explicitly.
Where do API keys and other secrets go?
In the project's Settings, under Secrets; the code reads them as environment variables. Random values such as session secrets can be generated in the console without anybody seeing them. A key found in an upload stops it before it goes live.
Can I deploy FastAPI from Claude Code or Codex?
Yes. Connect Agent Lab MCP once (one command, sign in in the browser, no API key), then say "deploy this FastAPI app". The tool creates the project, uploads, waits for the build and asks before going live. Connect MCP →
Is there a free way to host FastAPI?
The Free plan is NT$0: one size-S app that sleeps after 15 idle minutes, one size-S database, three static web pages, 100 build minutes and 5 GB of traffic a month, pausing at the limit instead of charging. Pro (US$29 a month before tax) keeps apps running and adds custom domains. Pricing →