.python Version -

The file should be placed in your project's and contain only the version number . File Name: .python-version (must start with a dot). File Content: A single line with the version string. Example: 3.12.2 or simply 3.12 . How to Create It

This is why is a fundamental best practice in modern Python development.

If a coworker pulls your repo and gets an error, it means they do not have that specific Python patch version installed locally. They will need to install it via their version manager (e.g., pyenv install ). To help tailor this setup to your workflow, let me know: .python version

pyenv finds the nearest .python-version file moving upwards. Place it in your project root. If you have nested projects, each can have its own file.

: Currently in alpha development, with a stable release expected in October 2026 [9, 17]. Evolution & Major Shifts The Python 2 to 3 "Schism" The file should be placed in your project's

When you open a terminal and change directories into a folder containing this file, your version manager reads the string and automatically configures your shell to use that exact Python executable. This eliminates the risk of accidentally running code with the wrong interpreter. Why Use a .python-version File?

.python-version file is a plain text file used by tools like pyenv to automatically define the Python version for a specific project directory. It ensures consistent environments across development, testing, and deployment, commonly identifying the desired version for platforms like Heroku. For more details, visit Heroku Dev Center Heroku Dev Center Specifying a Python Version - Heroku Dev Center Example: 3

You can dynamically read the file in your automated testing workflows. This prevents duplication by sourcing the version string directly from the repository.

This script will output a random string of characters, for example: aB9#kL!zX7@pQ2*mN$o .

: Guarantees that every developer on a team uses the exact same patch or minor version of Python.