Open source. Open possibilities.

Ruff is an extremely fast Python linter and code formatter written in Rust, designed to replace multiple tools like Flake8, Black, and isort with a single interface.

ShellCheck is a GPLv3 static analysis tool for bash/sh shell scripts that flags syntax issues, semantic problems, and portability pitfalls. It runs in terminals, editors, and CI pipelines, with output formats including JSON, CheckStyle XML, and GCC-compatible warnings.

Lintro is an MIT-licensed command-line tool that brings many linters, formatters, type checkers and security scanners together under one interface, with consistent reports, auto-fixing, Docker images and optional AI-assisted review using your own API key.

Whitaker provides opinionated Dylint lints for Rust to enforce readable code, sensible module sizes, and avoiding panics in production. Includes nine standard lints (e.g., banning expect() outside tests, module line limits) and configurable thresholds. Supports multiple languages for diagnostics.

A framework for managing and maintaining multi-language pre-commit hooks.

CoalLedger is a docs-health checking suite for AI coding agents — the documentation counterpart to CoalMine's code canaries. Seven canaries flag wrong, incomplete, stale, contradictory, broken, unreadable and (optionally) leaked documentation, with a bundled zero-dependency CommonMark+GFM AST engine, context-judged severity and choice-gated fixes.

SwiftLint is a widely-used open-source linter for Swift code that enforces style and conventions with over 200 configurable rules, integrating with Xcode, VS Code, CI pipelines, and more.