biome

Fast code formatter and linter for JavaScript, TypeScript, and CSS

TLDR

Initialize Biome in a project

$ biome init

Check code for errors (lint and format)

$ biome check [path/to/directory]

Format code

$ biome format --write [path/to/directory]

Lint code and show issues

$ biome lint [path/to/directory]

Fix auto-fixable lint issues

$ biome lint --write [path/to/directory]

Check a single file

$ biome check [path/to/file.js]

Output in JSON format

$ biome check --reporter=json [path/to/directory]

CI mode (fails on any issues)

$ biome ci [path/to/directory]

SYNOPSIS

biome command [options] [paths]

Biome is a fast code formatter, linter, and more for JavaScript, TypeScript, JSX, JSON, CSS, GraphQL, and (in newer releases) HTML. It is designed as a unified toolchain to replace ESLint, Prettier, and other tools with a single, faster alternative.Written in Rust, Biome provides exceptional performance - often 10-100x faster than JavaScript-based alternatives. It requires minimal configuration, with sensible defaults out of the box while remaining highly customizable through biome.json.The tool integrates formatting and linting into a single pass, reducing overhead. Editor integrations provide real-time feedback, and the CLI supports various output formats for CI systems.

PARAMETERS

init

Create a biome.json configuration file.

check

Run linter and formatter checks.

format

Format source files.

lint

Lint source files.

Check for CI environments (stricter mode).

migrate eslint | migrate prettier

Read an existing ESLint or Prettier config and port its settings into biome.json. Add --write to apply.

--write

Apply safe fixes and formatting to files (formerly --apply).

--fix

Alias of --write; apply safe fixes.

--unsafe

Also apply fixes marked unsafe (use with --write).

--only rule

Run only the given lint rule or group.

--skip rule

Skip the given lint rule or group.

--error-on-warnings

Exit with an error code when warnings are emitted.

--reporter format

Output format: summary, json, github, gitlab.

--config-path path

Path to configuration file.

--vcs-enabled bool

Use VCS ignore files (.gitignore).

--no-errors-on-unmatched

Don't error if no files match.

--diagnostic-level level

Minimum severity: info, warn, error.

CONFIGURATION

biome.json

Project-level configuration file controlling formatter settings, linter rules, file include/exclude patterns, and language-specific options. Created by `biome init`.

CAVEATS

Biome may not support all ESLint rules or Prettier options, and some projects with unusual configurations require adjustments during migration. Biome 2.0 (2025) added a plugin system and type-aware linting, but the plugin ecosystem is still much smaller than ESLint's. CSS, GraphQL, and HTML support are newer than the mature JS/TS support.

HISTORY

Biome emerged from Rome Tools, a project started by Sebastian McKenzie (creator of Babel) in 2020. When Rome Tools Inc. ceased operations in 2023, the community forked the project as Biome under a new governance model. The fork quickly gained traction, maintaining the performance-focused Rust implementation while accelerating development under community stewardship. Biome 2.0, released in 2025, introduced a plugin system and type-aware linting.

RESOURCES

Source code · Homepage · Documentation