Biome Linting

Fast, unified linting and formatting (10-25x faster than ESLint + Prettier).

Why Biome in 2026

Aspect Biome ESLint + Prettier

Speed ~200ms for 10k lines 3-5s

Config files 1 (biome.json) 4+

npm packages 1 binary 127+

Rules 421 Varies by plugins

Type inference Yes (v2.0+) Requires tsconfig

Quick Start

Install

npm install --save-dev --save-exact @biomejs/biome

Initialize

npx @biomejs/biome init

Check (lint + format)

npx @biomejs/biome check .

Fix

npx @biomejs/biome check --write .

CI mode (fails on errors)

npx @biomejs/biome ci .

Biome 2.0 Features

Type Inference: Reads .d.ts from node_modules for type-aware rules:

{ "linter": { "rules": { "nursery": { "noFloatingPromises": "error" // Catches unhandled promises } } } }

Multi-file Analysis: Cross-module analysis for better diagnostics.

Basic Configuration

{ "$schema": "https://biomejs.dev/schemas/2.0.0/schema.json", "formatter": { "enabled": true, "indentStyle": "space", "indentWidth": 2, "lineWidth": 100 }, "linter": { "enabled": true, "rules": { "recommended": true, "correctness": { "noUnusedVariables": "error", "noUnusedImports": "error" }, "suspicious": { "noExplicitAny": "warn" } } }, "javascript": { "formatter": { "quoteStyle": "single", "trailingCommas": "all" } } }

ESLint Migration

Auto-migrate configuration

npx @biomejs/biome migrate eslint --write

Common Rule Mappings:

ESLint Biome

no-unused-vars correctness/noUnusedVariables

no-console suspicious/noConsole

@typescript-eslint/* Most supported

eslint-plugin-react Most supported

eslint-plugin-jsx-a11y Most supported

CI Integration

.github/workflows/lint.yml

• uses: biomejs/setup-biome@v2
• run: biome ci .

Overrides for Gradual Adoption

{ "overrides": [ { "include": [".test.ts", ".spec.ts"], "linter": { "rules": { "suspicious": { "noExplicitAny": "off" } } } }, { "include": ["legacy/**"], "linter": { "enabled": false } } ] }

Key Decisions

Decision Recommendation

New vs migration Biome first for new projects; migrate existing gradually

Config strictness Start with recommended, tighten over time

CI strategy Use biome ci for strict mode, biome check for local

Type inference Enable for TypeScript projects (v2.0+)

Related Skills

• vite-advanced

• Build tooling integration

• react-server-components-framework

• React linting rules

• ci-cd-engineer

• CI pipeline setup

References

• ESLint Migration - Step-by-step migration

• Biome Config - Full configuration options

• Type-Aware Rules - Biome 2.0 type inference

• CI Integration - GitHub Actions setup