Ruff vs Spotless

Ruff is a Python linter and code formatter written in Rust, available free under a permissive open-source license. It includes more than 900 built-in lint rules, including native versions of popular Flake8 plugin rules, and can automatically correct violations such as unused imports. Its formatter aims to serve as a replacement for Black, though the documentation allows for differences in some cases. The built-in Ruff Language Server supplies diagnostics, fixes, and formatting; the documentation recommends pairing it with another Python language server for navigation and autocompletion. Setup guidance covers VS Code, Sublime Text, PyCharm, and Zed, while CI support includes GitHub Actions, GitLab CI/CD, and pre-commit hooks. Ruff can be installed through uv, pip, pipx, standalone installers, Homebrew, Conda, and other package managers. It supports configuration in pyproject.toml, ruff.toml, or .ruff.toml. A Bandit-derived rule group checks for common Python security issues. Ruff runs on Linux, macOS, and Windows, and is also published as a Docker image. The maker describes it as 10–100x faster than tools such as Flake8 and Black.

Spotless formats source code and can check files for formatting violations or apply fixes. It supports languages and formats including Java, Kotlin, JavaScript, Python, SQL, YAML, and Markdown, with formatter options such as Google Java Format, ktlint, Prettier, ESLint, Black, and ScalaFmt. The project integrates with Gradle and Maven and links to an external SBT integration. Its README links to VS Code and IntelliJ integrations. Spotless lists automatic idempotency and encoding safeguards for Gradle, Maven, and SBT. Git-based features include ratcheting from a Git reference for Gradle and Maven, and Git-defined line endings for all three build tools. Some capabilities, including ratcheting and fast incremental formatting, are unavailable in SBT. The repository identifies the license as Apache-2.0. Spotless is available for Linux, macOS, and Windows. DiffPlug directs questions to its forum and lists a technical support contact; security disclosures can be sent to [email protected]. Its plan listing includes a free plan at free, billed free forever with no registration required, and also lists a free trial.