---
title: bundleIdentifier
framework: extensionfoundation
role: symbol
role_heading: Instance Property
path: extensionfoundation/appextensionidentity/bundleidentifier
---

# bundleIdentifier

The bundle identifier of the app extension.

## Declaration

```swift
var bundleIdentifier: String { get }
```

## Discussion

Discussion During development, an app extension creator assigns a value to this string that incorporates the creator’s company name and the extension name. Bundle identifier strings use reverse-DNS notation.

## See Also

### Identifying the process

- [extensionPointIdentifier](extensionfoundation/appextensionidentity/extensionpointidentifier.md)
- [localizedName](extensionfoundation/appextensionidentity/localizedname.md)