The Python language is officially supported on the platform.

Detection

To ensure our deployment system considers your application as a Python application, a file Pipfile, requirements.txt, setup.py, poetry.lock or uv.lock should be present at the root of your project, defining the dependencies of your app.

Python Versions

Availability

The following versions of Python are available:

Selecting a Version

The default Python version on all stacks is the latest 3.13 version. You can, however, instruct the platform to use another version.

The buildpack looks for a Python version in the following places (in descending order of precedence):

• The runtime.txt file (deprecated)
• The .python-version file (recommended)
• The python_full_version field in the Pipfile.lock file (Pipenv users only)
• The python_version field in the Pipfile.lock file (Pipenv users only)

To instruct the platform to use a specific Python runtime, add a .python-version file to your app’s root directory and declare the Python version number to use in it.

This version can be either:

• The major Python version such as 3.12 (recommended)
• The full Python version such as 3.12.7

Dependencies

Recommended: pipenv

When the project is using pipenv and contains a Pipfile and a Pipfile.lock files, the following command is used to install dependencies:

pipenv install

Legacy: requirements.txt

If a requirements.txt file is present in your application, the dependencies will be installed respecting this file with:

pip install -r requirements.txt

Alternative: Poetry

If your project uses poetry and contains a poetry.lock file, the following command is used to install dependencies:

poetry sync --compile

Frameworks

We handle most of the common frameworks. Obviously, Django is among them. You need to configure your application to bind the port defined by the environment variable $PORT.

• Getting Started with Django

Specific Python Buildpack Hooks

You may want to trigger custom actions after a successful deployment. The postdeploy hook is exactly what you need. But your application may require some actions to be executed during the deployment.

The Python buildpack can execute two hooks: before and after the installation of Python and its dependencies. They must be located in the bin root folder of your application and be named pre_compile and post_compile.

Buildpack

More information at https://github.com/Scalingo/python-buildpack.

WEB_CONCURRENCY

The default level of concurrency is automatically defined, depending on the amount of memory available in the container running the app:

For further details about this calculation, please see the WEB_CONCURRENCY.sh script of the Python buildpack.

To override the automatically defined value, set the WEB_CONCURRENCY environment variable to the desired value.