Ultracite

A highly opinionated, zero-configuration linter and formatter.

Ultracite is a highly opinionated preset for Biome, designed to help you and your AI models write consistent and type-safe code without the hassle of configuration.

Quick Start

Install and initialize Ultracite in your project:

npx ultracite init

That's it! Ultracite will automatically format your code and fix lint issues every time you save. No configuration required.

Key Features

⚡ Subsecond Performance

Built in Rust for instant code analysis and processing. On-save checks feel seamless without interrupting your workflow.

🎯 Zero-Config by Design

Preconfigured rules optimized for Next.js, React, and TypeScript projects with sensible defaults. Customize when needed, but it works perfectly out of the box.

🛡️ Maximum Type Safety

Enforces strict type checking and best practices by default, catching type errors and preventing unsafe code patterns before they become problems.

🏗️ Monorepo Ready

Unified toolchain configuration across all packages and apps, eliminating thousands of lines of duplicate config files while maintaining consistency.

🤖 AI-Friendly

Ensures consistent code style and quality across all team members and AI models, eliminating debates over formatting and reducing code review friction. Supports GitHub Copilot, Cursor, Windsurf, Zed, Claude Code, and OpenAI Codex.

🔧 Intuitive and Robust

Automatically reformats code and fixes lint issues on save, with clear error reporting for issues that need manual attention.

How It Works

Once set up, Ultracite runs mostly in the background:

• Automatic formatting on every save
• Lint fixes applied automatically when possible
• Type safety enforced with strict rules
• Import organization and cleanup
• Accessibility improvements built-in

Because Biome is extremely fast, even on large projects, running Ultracite's checks is instantaneous and can comfortably run on every save without lag.

Command Line Usage

# Format your code
npx ultracite fix

# Check for lint issues
npx ultracite check

Tests

You can run tests with:

bun test

Check the coverage of the CLI with:

bun test:coverage

Read the docs for detailed setup instructions, configuration options, and examples.

Sponsors

Thank you to all our sponsors!

CodeRabbit

CodeRabbit helps you cut code review time & bugs in half. Supercharge your entire team with AI-driven contextual feedback. Supports all languages!