Monorepos

Use Ultracite in a monorepo with shared presets, workspace-aware config, and repo-wide editor defaults that stay consistent across packages.

Ultracite is designed to work out of the box with monorepos. Here’s how to use it with Turborepo.

Configuration

When initializing Ultracite, it will create the appropriate config file(s) in the root of your repository based on your chosen linter. This configuration applies to your entire monorepo.

my-turborepo/
├── apps/
├── packages/
├── turbo.json
└── oxlint.config.ts + oxfmt.config.ts (or .mts, biome.jsonc, eslint.config.mjs, etc.)

Different frameworks per workspace

When workspaces use different frameworks, scope each framework’s rules to its workspace so, for example, React rules don’t run on an Astro docs site. Pass --workspace-framework <path>=<framework> to init for each workspace and framework:

npx ultracite init --frameworks vitest --workspace-framework apps/web=react apps/web=tanstack apps/docs=astro

--frameworks still applies to the whole repository. For each workspace, init writes a config in that directory that extends the root config and adds the workspace’s presets, and installs what those presets need at the root. Editor extensions and the linters themselves read these configs too, so they report the same rules as ultracite check. Packages without a config of their own keep the root config.

init leaves a workspace config that already exists unchanged and tells you which presets to add. The configs it writes look like this, so you can also write or update them yourself.

Oxlint

import { defineConfig } from "oxlint";
import react from "ultracite/oxlint/react";
import tanstack from "ultracite/oxlint/tanstack";

import root from "../../oxlint.config.ts";

// Oxlint lints each file with its nearest config alone, so this extends the
// root config and repeats the properties that extends doesn't carry over.
export default defineConfig({
  extends: [root, react, tanstack],
  ignorePatterns: root.ignorePatterns,
  settings: root.settings,
});

Oxlint uses the config nearest each file instead of merging it with the root one. Extending the root config brings in its presets, rules and JS plugins, but not its ignorePatterns or settings, so the workspace config repeats them. In a workspace whose package.json doesn’t set "type": "module", the file is oxlint.config.mts.

Biome

{
  "$schema": "../../node_modules/@biomejs/biome/configuration_schema.json",
  "extends": [
    "ultracite/biome/core",
    "ultracite/biome/vitest",
    "../../biome.jsonc",
    "ultracite/biome/react",
    "ultracite/biome/tanstack",
  ],
  "root": false,
}

Biome’s "//" shorthand inherits the whole root config but can’t be combined with other extends entries. Extending the root config by path applies its own settings but not the presets it extends, so the workspace config lists the root’s extends first. When you change the root config’s extends, update the workspace configs to match.

ESLint

/* eslint-disable import-x/no-extraneous-dependencies, import-x/no-relative-packages -- imports the presets and config of the root package */
import react from "ultracite/eslint/react";
import tanstack from "ultracite/eslint/tanstack";

import root from "../../eslint.config.mjs";

// ESLint lints each file with its nearest config alone, so this spreads the
// root config before the workspace's presets.
export default [...root, ...react, ...tanstack];

ESLint also uses the config nearest each file, so the workspace config spreads the root config before its presets. The presets come from the root package and the root config sits in another package, which core’s import-x rules would flag. init disables only the rules that apply: none for a directory without its own package.json, and not import-x/no-extraneous-dependencies when the workspace lists ultracite as a dependency.

Adding scripts

Because Ultracite’s underlying tools are fast (especially the Rust-based Biome and Oxlint), you can run a single root script rather than creating separate scripts in each package.

ultracite init adds check and fix scripts to your root package.json. If you set Ultracite up by hand, add them yourself:

{
  "scripts": {
    "check": "ultracite check",
    "fix": "ultracite fix"
  }
}

Optionally, add these as root tasks in your turbo.json:

{
  "tasks": {
    "//#check": {},
    "//#fix": {
      "cache": false
    }
  }
}

You can now run turbo run check and turbo run fix from anywhere in your monorepo.