---
title: applicationIdentifier
framework: webkit
role: symbol
role_heading: Instance Property
path: webkit/wkwebextension/messageport/applicationidentifier
---

# applicationIdentifier

The unique identifier for the app to which this port should be connected.

## Declaration

```swift
var applicationIdentifier: String? { get }
```

## Discussion

Discussion This identifier is provided by the web extension and may or may not be used by the app. It’s up to the app to decide how to interpret this identifier.