Biome vs Ruff
Feature checklists rarely decide anything. What decides it is the pricing metric, who has to write the tests, and which limitation you can live with.
Entry price
Free and open source
Open sourceFree and open source
Open sourceWhat drives the bill
The metric that actually scales your invoice.
Free and open source. You pay in engineering time and CI minutes.
Free and open source. You pay in engineering time and CI minutes.
Free tier
Everything, self-hosted
Everything, self-hosted
Open source
MIT
MIT
Self-hostable
No-code authoring
Languages
Platforms
Fits teams
Adoption
Widely used
Biome / OSS community · since 2023
Category standard
Astral · since 2022
Strengths
- Dramatically faster than ESLint plus Prettier, which matters on pre-commit hooks.
- One binary and one config replaces two toolchains.
- Very good ESLint rule migration tooling.
- Replaces Flake8, isort, Black, pyupgrade and more with a single fast binary.
- Fast enough to run on every keystroke in the editor.
- Straightforward migration from existing Flake8 configurations.
Limitations
- Rule coverage does not yet match ESLint's plugin ecosystem.
- No support for framework-specific plugin ecosystems at ESLint's depth.
- Young project, so expect churn.
- Not every niche Flake8 plugin rule has been ported.
- Type checking is a separate concern — you still need mypy or ty.
- Rapid release cadence occasionally changes behaviour.
Best for
New JavaScript projects and teams frustrated by lint performance.
Every Python project.
All of these integrate with: VS Code, GitHub Actions.
Pricing last reviewed August 2026 and is indicative only — confirm on each vendor’s own page.