bun-src/docs/pm/workspaces.mdx

---
title: "Workspaces"
description: "Develop complex monorepos with multiple independent packages"
---

Bun supports [`workspaces`](https://docs.npmjs.com/cli/v9/using-npm/workspaces?v=true#description) in `package.json`. With workspaces, you develop several independent packages in a single repository, a _monorepo_.

A monorepo commonly has this structure:

```txt File Tree icon="folder-tree"
<root>
├── README.md
├── bun.lock
├── package.json
├── tsconfig.json
└── packages
    ├── pkg-a
    │   ├── index.ts
    │   ├── package.json
    │   └── tsconfig.json
    ├── pkg-b
    │   ├── index.ts
    │   ├── package.json
    │   └── tsconfig.json
    └── pkg-c
        ├── index.ts
        ├── package.json
        └── tsconfig.json
```

The `"workspaces"` key in the root `package.json` lists the subdirectories to treat as workspaces. By convention, they live in a directory called `packages`.

```json package.json icon="file-json"
{
  "name": "my-project",
  "version": "1.0.0",
  "workspaces": ["packages/*"],
  "devDependencies": {
    "example-package-in-monorepo": "workspace:*"
  }
}
```

<Note>
  **Glob support** — Bun supports full glob syntax in `"workspaces"`, including negative patterns such as
  `!**/excluded/**`. See [supported glob patterns](/runtime/glob#supported-glob-patterns).
</Note>

```json package.json icon="file-json"
{
  "name": "my-project",
  "version": "1.0.0",
  "workspaces": ["packages/**", "!packages/**/test/**", "!packages/**/template/**"]
}
```

Each workspace has its own `package.json`. To reference another package in the monorepo, use a semver range or the workspace protocol (for example `workspace:*`) as the version in your `package.json`.

```json packages/pkg-a/package.json icon="file-json"
{
  "name": "pkg-a",
  "version": "1.0.0",
  "dependencies": {
    "pkg-b": "workspace:*"
  }
}
```

`bun install` installs dependencies for all workspaces in the monorepo, de-duplicating packages if possible. To install dependencies for specific workspaces only, use the `--filter` flag.

```bash
# Install dependencies for all workspaces starting with `pkg-` except for `pkg-c`
bun install --filter "pkg-*" --filter "!pkg-c"

# Paths can also be used. This is equivalent to the command above.
bun install --filter "./packages/pkg-*" --filter "!pkg-c" # or --filter "!./packages/pkg-c"
```

When publishing, Bun replaces `workspace:` versions with the package's `package.json` version:

```
"workspace:*" -> "1.0.1"
"workspace:^" -> "^1.0.1"
"workspace:~" -> "~1.0.1"
```

A specific version takes precedence over the package's `package.json` version:

```
"workspace:1.0.2" -> "1.0.2" // Even if current version is 1.0.1
```

Workspaces have a few major benefits.

- **Split code into logical parts.** If one package relies on another, add it as a dependency in `package.json`. If package `b` depends on `a`, `bun install` installs your local `packages/a` directory into `node_modules` instead of downloading it from the npm registry.
- **Bun can de-duplicate dependencies.** If `a` and `b` share a common dependency, Bun _hoists_ it to the root `node_modules` directory. This saves disk space and minimizes the "dependency hell" of multiple versions of a package installed at once.
- **Run scripts in multiple packages.** Use the [`--filter` flag](/pm/filter) to run `package.json` scripts in several packages at once, or `--workspaces` to run scripts across all workspaces.

## Share versions with Catalogs

When many packages need the same dependency versions, define those versions once
in a catalog in the root `package.json` and reference them from your workspaces
with the `catalog:` protocol. Updating the catalog updates every package that
references it. See [Catalogs](/pm/catalogs).

<Note>
⚡️ **Speed** — Installs are fast, even for big monorepos. Bun installs the [Remix](https://github.com/remix-run/remix) monorepo in about `500ms` on Linux.

- 28x faster than `npm install`
- 12x faster than `yarn install` (v1)
- 8x faster than `pnpm install`

<Image src="https://user-images.githubusercontent.com/709451/212829600-77df9544-7c9f-4d8d-a984-b2cd0fd2aa52.png" />
</Note>