Boundaries

Experimental feature - See RFC

Full docs: https://turborepo.dev/docs/reference/boundaries

Boundaries enforce package isolation by detecting:

1. Imports of files outside the package's directory
2. Imports of packages not declared in package.json dependencies

Usage

turbo boundaries

Run this to check for workspace violations across your monorepo.

Tags

Tags allow you to create rules for which packages can depend on each other.

Adding Tags to a Package

// packages/ui/turbo.json
{
  "tags": ["internal"]
}

Configuring Tag Rules

Rules go in root turbo.json:

// turbo.json
{
  "boundaries": {
    "tags": {
      "public": {
        "dependencies": {
          "deny": ["internal"]
        }
      }
    }
  }
}

This prevents public-tagged packages from importing internal-tagged packages.

Rule Types

Allow-list approach (only allow specific tags):

{
  "boundaries": {
    "tags": {
      "public": {
        "dependencies": {
          "allow": ["public"]
        }
      }
    }
  }
}

Deny-list approach (block specific tags):

{
  "boundaries": {
    "tags": {
      "public": {
        "dependencies": {
          "deny": ["internal"]
        }
      }
    }
  }
}

Restrict dependents (who can import this package):

{
  "boundaries": {
    "tags": {
      "private": {
        "dependents": {
          "deny": ["public"]
        }
      }
    }
  }
}

Using Package Names

Package names work in place of tags:

{
  "boundaries": {
    "tags": {
      "private": {
        "dependents": {
          "deny": ["@repo/my-pkg"]
        }
      }
    }
  }
}

Key Points

• Rules apply transitively (dependencies of dependencies)
• Helps enforce architectural boundaries at scale
• Catches violations before runtime/build errors