Biome

Biome is a performant toolchain for web projects that provides fast formatting, linting, and code quality tools in a single unified package. Built on a Rust core for maximum performance, Biome offers 97% compatibility with Prettier for formatting and includes over 340 linting rules from ESLint, typescript-eslint, and other sources. It's designed for interactive use within editors with LSP support and can format and lint malformed code in real-time with detailed diagnostics.

Package Information

• Package Name: @biomejs/biome
• Package Type: npm
• Language: JavaScript/TypeScript (wrapper around native Rust binaries)
• Installation: npm install --save-dev --save-exact @biomejs/biome
• Requirements: Node.js >= 14.21.3
• Documentation: https://biomejs.dev/

Core Usage

Biome is invoked via the biome command-line interface. The CLI provides multiple commands for different workflows.

Basic Commands

# Format files
npx @biomejs/biome format --write ./src

# Lint files and apply safe fixes
npx @biomejs/biome lint --write ./src

# Run format, lint, and import sorting with safe fixes
npx @biomejs/biome check --write ./src

# Check all files in CI (read-only mode)
npx @biomejs/biome ci ./src

Configuration

Biome uses a biome.json or biome.jsonc configuration file:

{
  "$schema": "https://biomejs.dev/schemas/2.3.8/schema.json",
  "formatter": {
    "enabled": true,
    "indentStyle": "space",
    "indentWidth": 2,
    "lineWidth": 80
  },
  "linter": {
    "enabled": true,
    "rules": {
      "recommended": true
    }
  }
}

Basic Usage

# Initialize a new Biome project
npx @biomejs/biome init

# Format and lint a project
npx @biomejs/biome check --write

# Run checks in CI environment
npx @biomejs/biome ci

Architecture

Biome consists of several key components:

• CLI Interface: Node.js wrapper that spawns platform-specific native binaries
• Native Binaries: Rust-based core distributed as platform-specific optional dependencies
• Formatter Engine: Fast formatting with Prettier compatibility
• Linter Engine: Rule-based linting with over 340 rules
• LSP Server: Language Server Protocol support for editor integration
• Configuration System: JSON-based configuration with extends, overrides, and language-specific settings
• VCS Integration: Git integration for staged and changed file detection
• Daemon Mode: Optional server mode for faster repeated invocations

Capabilities

Core Commands

Primary commands for formatting, linting, and checking code.

# Format files
biome format [OPTIONS] [PATHS]...

# Lint files
biome lint [OPTIONS] [PATHS]...

# Run formatter, linter, and import sorting
biome check [OPTIONS] [PATHS]...

# CI mode (read-only)
biome ci [OPTIONS] [PATHS]...

Core Commands

Configuration Management

Initialize, migrate, and manage Biome configuration.

# Initialize new project
biome init [--jsonc]

# Migrate from other tools
biome migrate [prettier|eslint] [OPTIONS]

Configuration file structure:

interface BiomeConfiguration {
  $schema?: string;
  root?: boolean;
  extends?: string[];
  files?: FilesConfiguration;
  formatter?: FormatterConfiguration;
  linter?: LinterConfiguration;
  assist?: AssistConfiguration;
  javascript?: JavaScriptConfiguration;
  json?: JsonConfiguration;
  css?: CssConfiguration;
  graphql?: GraphqlConfiguration;
  html?: HtmlConfiguration;
  vcs?: VcsConfiguration;
  overrides?: OverrideConfiguration[];
  plugins?: string[];
}

Configuration

Global CLI Options

Options available across most commands for controlling output, diagnostics, and behavior.

# Color control
--colors <off|force>

# Configuration path
--config-path <PATH>

# Verbosity
--verbose
--max-diagnostics <none|NUMBER>
--diagnostic-level <info|warn|error>

# Error handling
--skip-parse-errors
--error-on-warnings
--no-errors-on-unmatched

# Reporting format
--reporter <json|json-pretty|github|junit|summary|gitlab|checkstyle|rdjson>

# Logging
--log-file <PATH>
--log-level <none|debug|info|warn|error>
--log-kind <pretty|compact|json>

# Server mode
--use-server

Global Options

Environment Variables

Environment variables that control Biome's behavior.

# Biome-specific
BIOME_CONFIG_PATH   # Path to configuration file
BIOME_BINARY        # Override native binary path
BIOME_LOG_PATH      # Daemon log directory
BIOME_LOG_PREFIX_NAME  # Log file prefix
BIOME_THREADS       # Thread count

# Standard variables
NO_COLOR            # Disable color output
TERM                # Terminal type

Environment Variables

Advanced Features

Additional capabilities for debugging, search, and server management.

# Search with GritQL patterns (experimental)
biome search <PATTERN> [PATHS]...

# Print debugging information
biome rage [OPTIONS]

# Show rule documentation
biome explain <RULE_NAME>

# Daemon server management
biome start [OPTIONS]
biome stop

# LSP server
biome lsp-proxy [OPTIONS]

# Clean daemon logs
biome clean

Advanced Features

Exit Codes

Biome uses standard Unix exit codes:

• 0 - Success (no errors)
• 1 - Failure (errors occurred)

Exit code behavior:

• Diagnostics with severity >= Error result in exit code 1
• With --error-on-warnings, warnings result in exit code 1
• Configuration errors result in exit code 1
• No files matched (without --no-errors-on-unmatched) results in exit code 1

Supported Languages

Biome supports formatting and linting for:

• JavaScript (.js, .mjs, .cjs)
• TypeScript (.ts, .mts, .cts)
• JSX/TSX (.jsx, .tsx)
• JSON (.json, .jsonc)
• CSS (.css)
• GraphQL (.graphql, .gql)
• HTML (.html, .htm)
• Vue (.vue - with caveats)
• Astro (.astro - with caveats)
• Svelte (.svelte - with caveats)

Platform Support

Biome provides native binaries for:

• Windows: x64, arm64
• macOS: x64 (Intel), arm64 (Apple Silicon)
• Linux: x64, arm64 (glibc and musl variants)

The npm package automatically installs the appropriate binary for your platform via optional dependencies.