419 Biome 7c46c8b2

Biome

Research Date: 2026-02-23 Source URL: https://biomejs.dev GitHub Repository: https://github.com/biomejs/biome Version at Research: v2.4.3 License: MIT OR Apache 2.0

Overview

Biome is a high-performance, all-in-one toolchain for web projects built in Rust that combines formatting (97% Prettier compatibility), linting (450+ rules from ESLint/typescript-eslint), and import organization into a single binary. It runs ~35× faster than Prettier, requires zero configuration to get started, provides first-class LSP support for editor integration, and in v2 introduced type-aware linting without requiring the TypeScript compiler — making it a drop-in replacement for the ESLint + Prettier toolchain.

Problem Addressed

Key Statistics

Key Features

Formatting

• 97% compatibility with Prettier for JS, TS, JSX, TSX, JSON, CSS, GraphQL, HTML
• Formats malformed code during editing via LSP
• ~35× faster than Prettier on large codebases
• Configurable indent style (space/tab), indent width, line width, quote style, trailing commas, semicolons

Linting

• 450+ rules sourced from ESLint, typescript-eslint, and additional sources
• Rule categories: correctness, complexity, style, suspicious, performance, accessibility, security, nursery
• Safe and unsafe fix suggestions with one-command auto-apply
• Detailed diagnostic output showing exact problem location and remediation

Type-Aware Linting (v2)

• New type inference engine independent of the TypeScript compiler
• Multi-file analysis: scans project and node_modules to build type graph
• ~75% detection coverage vs typescript-eslint for rules like noFloatingPromises with no tsc overhead
• Opt-in via project domain rules; does not affect performance for non-type-aware linting
• Full monorepo support: uses the correct package.json per package

Import Organization

• Automatic import sorting and deduplication via assist.actions.source.organizeImports
• Controlled via biome check --write or as part of CI via biome ci

Editor Integration

• First-party extensions for VS Code, IntelliJ, and Zed
• Community extensions for Vim, Neovim, Sublime Text
• LSP server with full error recovery and format-on-save support
• Formats and lints malformed code as you type

Zero-Config & Standalone

• Works out of the box with npx @biomejs/biome check --write ./src
• Optional biome.json for project-level configuration (npx @biomejs/biome init)
• Standalone binary available without Node.js
• Git VCS integration: respects .gitignore patterns via vcs.useIgnoreFile

CI Integration

• biome ci command enforces code quality in CI pipelines (equivalent to biome check without writes)
• GitHub Actions and GitLab CI recipes provided in official documentation
• Exits with non-zero status on any violation for gate enforcement

Technical Architecture

Core Design

Biome is built in Rust with an architecture inspired by rust-analyzer, providing:

• Shared parser: A single parser produces a full-fidelity syntax tree (including trivia like whitespace and comments) used by both the formatter and linter — no double-parsing overhead
• Error recovery: Parser continues after syntax errors, enabling formatting and linting of malformed code
• Parallel execution: Files are processed in parallel using Rayon-based work-stealing
• Single binary: All tools ship in one executable, eliminating version coordination between tools

v2 File Scanner

biome check --write ./src
    ↓
File Scanner (opt-in for project domain rules)
    ↓ discovers all .js/.ts/.jsx/.tsx files
Parallel parser farm (one thread per CPU core)
    ↓ produces full-fidelity CSTs
Formatter pass → emit formatted text
    ↓
Linter pass (per-file rules) → collect diagnostics
    ↓
Type Inference Engine (project domain rules only)
    ↓ queries multi-file type graph
Type-aware lint rules → additional diagnostics
    ↓
Write fixes + report summary

Configuration Hierarchy

biome.json (project root)
    ↓ overridden by
packages/pkg-a/biome.json (nested config, v2+)
    ↓ overridden by
CLI flags
    ↓ overridden by
BIOME_* environment variables

Installation & Usage

Installation

# As a dev dependency (recommended)
npm i -D -E @biomejs/biome

# pnpm
pnpm add -D -E @biomejs/biome

# Standalone binary (no Node.js required)
# See: https://biomejs.dev/guides/manual-installation/

Quick Start

# Initialize biome.json
npx @biomejs/biome init

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

# Lint with safe auto-fixes
npx @biomejs/biome lint --write ./src

# Format + lint + organize imports (recommended)
npx @biomejs/biome check --write ./src

# CI enforcement (no writes, exits non-zero on violations)
npx @biomejs/biome ci ./src

Example biome.json

{
  "$schema": "https://biomejs.dev/schemas/2.4.3/schema.json",
  "vcs": { "enabled": true, "clientKind": "git", "useIgnoreFile": true },
  "formatter": {
    "enabled": true,
    "indentStyle": "space",
    "indentWidth": 2,
    "lineWidth": 100
  },
  "linter": {
    "enabled": true,
    "rules": { "recommended": true }
  },
  "javascript": {
    "formatter": { "quoteStyle": "single", "semicolons": "always" }
  },
  "assist": {
    "enabled": true,
    "actions": { "source": { "organizeImports": "on" } }
  }
}

Migrate from ESLint + Prettier

# Automated migration command
npx @biomejs/biome migrate eslint --write
npx @biomejs/biome migrate prettier --write

Relevance to Claude Code Development

Applications

This repository already uses Biome (biome.json at repo root) for JS/TS linting and formatting via CI (.github/workflows/code-quality.yml) and pre-commit hooks (.pre-commit-config.yaml). The current config uses v2.3.13 schema with recommended rules and single-quote JS formatting.

Enforcing Code Quality in Hook Scripts:

• Claude Code hooks (.claude/hooks/*.cjs, plugins/*/hooks/*.cjs) are CommonJS Node.js files that benefit from Biome's linting and formatting
• biome check --write can be added to the pre-commit hook pipeline for hook script quality

CI Quality Gate Integration:

• npx @biomejs/biome ci already runs in CI and can be extended with project-domain type-aware rules
• Exit-code-based gate pattern directly supports Claude Code's pre-push quality enforcement

Patterns Worth Adopting

Single-Tool Simplicity over Toolchain Composition:

• Biome's single-binary approach (formatter + linter + import organizer) eliminates the "N tools, N config files, N version conflicts" problem
• Skills and plugins can document "use biome check --write for JS/TS" as the single authoritative command

Zero-Config First, Config When Needed:

• Biome works with zero configuration — a pattern worth applying to Claude Code plugin defaults
• Optional biome.json only when project-level overrides are necessary

Opt-In Performance Cost:

• v2 type inference is opt-in, not default — isolating expensive multi-file scans to rules that need them
• Pattern: define expensive analysis as opt-in with explicit user consent (analogous to --all-files vs targeted pre-commit runs)

Unified CLI Verbs:

• format, lint, check (all), ci (CI-only no-write) provide clear semantic separation
• Pattern for skill CLI design: discrete verbs for distinct phases of a workflow

Integration Opportunities

Upgrade biome.json to v2.4.3 Schema:

• Current repo config references schema 2.3.13; upgrading to 2.4.3 enables access to new v2 rules and HTML support
• Run npx @biomejs/biome migrate --write to auto-apply breaking config changes

Enable Type-Aware Rules:

• Add project domain rules to biome.json to detect floating promises, undefined type access, and other type errors in hook scripts
• Provides ESLint @typescript-eslint/no-floating-promises equivalent without TypeScript compiler dependency

Claude Code Plugin for Biome Diagnostics:

• A skill that runs biome check --json ./src and parses the structured JSON output to present lint findings in a structured agent-readable format
• Integration point: plugins/holistic-linting/skills/biome-diagnostics/

Pre-commit Hook for Hook Scripts:

• Add npx @biomejs/biome check --write as a pre-commit stage specifically for .cjs hook files
• Ensures all Claude Code hooks maintain consistent style without separate ESLint config

References

• Biome Official Website (accessed 2026-02-23)
• biomejs/biome GitHub Repository (accessed 2026-02-23)
• Biome Getting Started Guide (accessed 2026-02-23)
• Biome v2 Release Announcement (accessed 2026-02-23)
• Biome v2.3 Release - Vue/Svelte/Astro Support (accessed 2026-02-23)
• Biome Roadmap 2025 (accessed 2026-02-23)
• Biome Linter Rules Reference (accessed 2026-02-23)
• Biome Configuration Reference (accessed 2026-02-23)

Freshness Tracking