---
url: /docs/replacements/is-builtin-module.md
description: >-
  Native Node.js alternatives to the is-builtin-module package for checking
  built-in modules
---

# Replacements for `is-builtin-module`

## `isBuiltin` (native, since Node.js 16.x)

For determining if a module is built-in or not, you can use [isBuiltin](https://nodejs.org/api/module.html#moduleisbuiltinmodulename):

```ts
import { isBuiltin } from 'node:module' // [!code ++]
import isBuiltinModule from 'is-builtin-module' // [!code --]

isBuiltin('fs') // true [!code ++]
isBuiltinModule('fs') // true [!code --]
```

## `builtInModules` (native, since Node.js 6.x and 15.x)

Before Node.js 16.x, `isBuiltin` was not available, so you need to implement your own check using [builtinModules](https://nodejs.org/api/module.html#modulebuiltinmodules):

```ts
import { builtinModules } from 'node:module' // [!code ++]
import isBuiltinModule from 'is-builtin-module' // [!code --]

function isBuiltin(moduleName) { // [!code ++]
  const name = moduleName.startsWith('node:') // [!code ++]
    ? moduleName.slice(5) // [!code ++]
    : moduleName // [!code ++]
  return builtinModules.includes(name) // [!code ++]
} // [!code ++]

isBuiltin('fs') // true [!code ++]
isBuiltinModule('fs') // true [!code --]
```