Biome
Fast all-in-one JavaScript/TypeScript linter and formatter — Rust-based tool that replaces ESLint + Prettier in a single binary. Biome features: biome format (Prettier-compatible formatting), biome lint (200+ lint rules), biome check (format + lint together), biome ci (CI mode, no writes), biome migrate eslint (migrates ESLint config), VS Code extension, editor integration, monorepo support, biome.json config, import sorting, JSX/TSX support, CSS/JSON formatting, and 20-50x faster than ESLint + Prettier. Drop-in replacement for Prettier with 96%+ compatibility. Forked from Rome.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
Local static analysis tool — no network access, no data collection. Biome binary is a single self-contained Rust binary — minimal supply chain attack surface compared to ESLint's large Node.js dependency tree. Download from official releases or npm @biomejs/biome.
⚡ Reliability
Best When
Setting up a new JavaScript/TypeScript agent project that needs fast, zero-config formatting and linting — Biome provides Prettier-compatible formatting and 200+ lint rules in a single fast binary without the ESLint + Prettier configuration overhead.
Avoid When
Your agent project requires specific ESLint plugins (react-hooks, security rules, custom rules), you have existing complex ESLint configs that can't migrate, or you need to lint languages beyond JS/TS/CSS/JSON.
Use Cases
- • Agent codebase formatting — biome format --write src/ — formats all JS/TS/JSON/CSS files in agent codebase 50x faster than Prettier; biome format --write agent.ts fixes indentation, semicolons, quotes in under 100ms; no .prettierrc config needed for defaults
- • Agent CI lint check — biome ci src/ — lints and checks formatting without writing; exits non-zero on lint errors or unformatted files; agent CI fails fast on code quality issues; biome ci runs in seconds vs ESLint minutes for large codebases
- • Agent ESLint migration — biome migrate eslint --write — reads .eslintrc.json and generates biome.json with equivalent rules; agent projects migrate from ESLint to Biome without manually rewriting config; 80% of ESLint rules have Biome equivalents
- • Agent import organization — biome check --apply-unsafe src/ with organizeImports enabled sorts imports alphabetically and removes unused; agent TypeScript files get clean import sections without manual sorting; single command fixes formatting, linting, and imports
- • Agent pre-commit hooks — biome check --staged in .husky/pre-commit; only lint and format staged files; agent commits are blocked if lint errors exist; faster than lint-staged + ESLint + Prettier combination
Not For
- • ESLint plugin ecosystem — Biome doesn't support ESLint plugins (eslint-plugin-react-hooks, eslint-plugin-security, etc.); agent projects requiring specific ESLint plugins must stay on ESLint
- • Non-JS languages — Biome formats CSS, JSON, JS, TS only; for Python/Ruby/Go formatting use language-specific formatters (Black, RuboCop, gofmt)
- • Custom lint rule authoring — Biome lint rules are compiled Rust; cannot write custom JS-based lint rules like ESLint; agent projects with custom business logic rules must use ESLint
Interface
Authentication
No auth — local CLI tool.
Pricing
Biome is MIT and Apache 2.0 dual-licensed. Free for all use.
Agent Metadata
Known Gotchas
- ⚠ Biome formatter differs from Prettier in edge cases — biome format aims for 96% Prettier compatibility but not 100%; trailing commas, bracket spacing, and JSX attribute formatting may differ; agent projects switching from Prettier get format churn on first biome format run; commit Prettier→Biome migration as separate commit
- ⚠ biome.json required for non-default config — without biome.json, Biome uses opinionated defaults; agent projects with specific indent width, quote style, or line width must create biome.json; biome init generates starter biome.json; defaults use 2-space indent and double quotes
- ⚠ ESLint rule migration is partial — biome migrate eslint converts ~80% of rules; rules without Biome equivalents are dropped silently; agent projects must manually audit which ESLint rules have no Biome equivalent and decide whether to accept the gap or keep ESLint for specific files
- ⚠ biome check --apply vs --apply-unsafe differ — --apply fixes safe issues (formatting, some lint); --apply-unsafe applies suggestions that might change code behavior; agent CI should use --apply (safe) not --apply-unsafe; document why unsafe is used if agent CI applies unsafe fixes
- ⚠ Monorepo root vs project biome.json — biome.json in root applies to all; nested biome.json overrides for that directory; agent monorepos with per-package configs must understand override semantics; biome merges root and local config (local wins on conflicts) not replaces
- ⚠ VS Code extension conflicts with Prettier extension — if both Biome VS Code extension and Prettier extension are installed, formatting conflicts occur on save; agent development environments must disable Prettier extension and set biome as default formatter in .vscode/settings.json
Alternatives
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Scores are editorial opinions as of 2026-03-07.