Python on Miren

Miren auto-detects Python apps and builds a container image for you — no Dockerfile required. It recognizes pip, Pipenv, Poetry, and uv, and configures a start command for common web frameworks.

Let your agent do this

Ask your AI coding agent to "set up this Python app on Miren" after installing the Miren agent skills. It detects your framework and package manager, proposes a start command, wires up environment variables, and deploys — using this page as its reference.

Do you need a Dockerfile?

No. Miren detects Python from a requirements.txt, Pipfile, pyproject.toml, or uv.lock and builds the image automatically. The default Python version is 3.11; override it in .miren/app.toml if you need another.

Provide a Dockerfile.miren only if your build needs custom system packages or steps that don't fit detection — see Using Dockerfile.miren.

Set up the app

From your project root, initialize and deploy:

miren init
miren deploy

CLIENT

miren init scaffolds .miren/app.toml and scans your project for the environment variables it needs. miren deploy uploads your code, builds the image, and activates the new version. Preview what Miren detects — stack, package manager, and start command — without building:

miren deploy --analyze

CLIENT

Package managers

Miren picks the install command from the files in your repo:

File	Package manager	Install command
Pipfile	pipenv	pipenv install --deploy
uv.lock	uv	uv sync --frozen
pyproject.toml	poetry	poetry install --no-root
requirements.txt	pip	pip install -r requirements.txt

Start command

Miren detects your web framework and configures a start command. You can always override it with a Procfile or the command field in .miren/app.toml.

Framework	Detected start
FastAPI	fastapi run
Django	gunicorn or uvicorn
Flask	gunicorn
Gunicorn / Uvicorn	gunicorn / uvicorn

Your server must bind to 0.0.0.0 on $PORT — Miren injects PORT and routes traffic to it. A Procfile makes this explicit:

# gunicorn (Flask / Django / WSGI)
web: gunicorn app:app --bind 0.0.0.0:$PORT

# Celery background worker
worker: celery -A tasks worker --loglevel=info

Pick a single web: line for your app. For an ASGI app, use uvicorn instead:

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

With uv, prefix the command:

web: uv run gunicorn app:app --bind 0.0.0.0:$PORT

See Services for running a worker alongside your web process.

Environment variables

Set variables with miren env set. Use -e for plain values and -s for secrets (masked in output and logs):

miren env set -e LOG_LEVEL=info
miren env set -s DATABASE_URL
miren env set -s SECRET_KEY

CLIENT

miren env set -s SECRET_KEY (no value) prompts with masked input. You can also declare variables in .miren/app.toml:

[[env]]
key = "DATABASE_URL"
value = ""
required = true
sensitive = true
description = "Postgres connection string"

See App Configuration — Environment Variables.

Agent quick reference

• Detection: requirements.txt, Pipfile, pyproject.toml, or uv.lock
• Default version: Python 3.11 (override via [build] version in .miren/app.toml)
• Install: pipenv / uv / poetry / pip, chosen by manifest (see table above)
• Start command: bind 0.0.0.0:$PORT; FastAPI/Django/Flask auto-detected, else set a Procfile
• Env vars: miren env set -e KEY=VALUE, -s for secrets, or [[env]] in app.toml
• Dockerfile: not needed; add Dockerfile.miren only for custom builds

Next steps

• Supported Languages — Python — full build detail
• App Configuration — customize .miren/app.toml
• Services — web + workers
• Deployment — how deploys build and activate