Ultracite

Ultracite is a zero-config Biome preset designed for both humans and LLMs. It's 35x faster than ESLint and Prettier combined.

Ultracite provides AI-ready formatting and linting rules through Biome. This boilerplate comes pre-configured with Ultracite presets for core JavaScript/TypeScript and React code.

What is Ultracite?

Ultracite is a curated set of Biome presets that:

Enforces consistent code style across your codebase
Provides rules optimized for both human readability and LLM understanding
Runs 35x faster than traditional ESLint + Prettier setups
Works seamlessly with AI coding assistants

Configuration

Ultracite is configured in biome.json at the root of your project:

{
  "$schema": "./node_modules/@biomejs/biome/configuration_schema.json",
  "files": {
    "ignoreUnknown": false,
    "includes": [
      "**",
      "!**/.next",
      "!**/dist",
      "!**/.turbo",
      "!**/dev-dist",
      "!**/.zed",
      "!**/.vscode",
      "!**/routeTree.gen.ts",
      "!**/src-tauri",
      "!**/.nuxt",
      "!bts.jsonc",
      "!**/.expo",
      "!**/.wrangler",
      "!**/.alchemy",
      "!**/.svelte-kit",
      "!**/wrangler.jsonc",
      "!**/.source"
    ]
  },
  "extends": [
    "ultracite/core",
    "ultracite/react"
  ]
}

The configuration uses two Ultracite presets:

ultracite/core: Core JavaScript/TypeScript rules
ultracite/react: React-specific rules and best practices

Usage

Run Formatting and Linting

Format and lint your entire codebase:

bun run check

This command:

Checks all files for linting issues
Auto-fixes issues where possible
Formats code according to Ultracite rules

Editor Integration

Most modern editors have Biome support via extensions:

VS Code: Install the Biome extension
Cursor: Biome is built-in
Zed: Biome support via extensions

Once installed, your editor will:

Show linting errors inline
Auto-format on save (if configured)
Provide quick fixes for common issues

CI/CD Integration

Add a check step to your CI pipeline:

# Example GitHub Actions
- name: Check code formatting
  run: bun run check

This ensures all code follows Ultracite rules before merging.

What Rules Are Enabled?

Ultracite includes hundreds of rules covering:

Code Quality: Enforces best practices and avoids common pitfalls
Accessibility: Ensures your React components are accessible
Performance: Prevents performance anti-patterns
Security: Catches potential security issues
React Best Practices: Follows React 19+ conventions

Key rules include:

No any types
Proper React hooks usage
Accessible components
Consistent code style
Modern JavaScript patterns

Customization

While Ultracite works great out of the box, you can extend or override rules in biome.json:

{
  "extends": [
    "ultracite/core",
    "ultracite/react"
  ],
  "linter": {
    "rules": {
      "recommended": true,
      "suspicious": {
        "noExplicitAny": "off"  // Override specific rule
      }
    }
  }
}

Benefits for AI Assistants

Ultracite's rules are designed to be:

LLM-friendly: Consistent patterns that AI assistants can learn from
Predictable: Code structure that's easy for AI to understand
Documented: Rules that provide context for AI code generation

When AI assistants read your codebase, they see:

Consistent formatting patterns
Clear code structure
Well-defined conventions

This helps AI assistants generate code that matches your project's style automatically.