Pylint

Pylint is a static code analysis tool for Python that checks for errors, enforces coding standards, and looks for code smells. Originally created by Sylvain Thenault in 2003 and now maintained by Pierre Sassoulas and the Python community, Pylint is one of the oldest and most comprehensive Python linters, with over 5,500 stars as of 2026. Unlike faster linters like Flake8 or Ruff that focus on style and simple errors, Pylint performs deep analysis of code structure and patterns. Key features include: comprehensive error checking (detecting syntax errors, undefined variables, unused imports, unused variables, unreachable code, missing docstrings, and over 400 other message types), coding style enforcement (checking PEP 8 compliance including naming conventions, line length, indentation, and import ordering), code complexity metrics (measuring cyclomatic complexity, maintainingability index, and code duplication detection), refactoring suggestions (identifying code smells like too many arguments, too many local variables, too many branches, too many statements, and similar patterns that reduce code quality), type checking (basic type inference and checking for type mismatches, though less comprehensive than mypy), custom checkers (writing custom Python checker plugins to enforce project-specific rules and conventions), configuration via pylintrc (granular control over which checks are enabled/disabled, message severity, and per-module overrides), message control (inline comments to disable specific checks on specific lines with pylint disable), confidence levels (categorizing messages by confidence: high, control_flow, inference, and undefined node), JSON output (for integration with CI/CD pipelines and IDE integrations), and integration with VS Code, PyCharm, Vim, Emacs, and pre-commit hooks.