Installation with multiple interpreters

Pylint runs inside a real Python interpreter. For most projects, the most reliable way to check code that supports multiple Python versions is therefore to run Pylint with the oldest Python version that the project supports. This makes the parser, standard library, and import environment match the project's compatibility floor.

Sometimes the lint environment intentionally uses a newer interpreter. For example, a pre-commit configuration might standardize all development tools on Python 3.13 while the project still supports Python 3.10. In that case, set py-version to the oldest supported version:

[tool.pylint.main]
py-version = "3.10"

The equivalent command-line option is --py-version=3.10. Without an explicit value, py-version defaults to the version of Python that runs Pylint.

py-version tells version-aware checks which Python features are available to every supported interpreter. For example, it prevents Pylint from suggesting a refactoring that requires a version newer than Python 3.10 and allows the unsupported-version checker to report syntax that Python 3.10 cannot use. It does not switch the interpreter that runs Pylint or emulate that interpreter's complete standard library and runtime behavior, so running Pylint on the oldest supported version remains preferable when practical.

Pylint does not guarantee that py-version will continue to support every end-of-life Python release indefinitely. If current Pylint cannot analyse the project's oldest supported release, the best available fallback may be an older Pylint that still runs on that interpreter, without the fixes and features added to later Pylint releases.