---
title: NSUserActivityPersistentIdentifier
framework: foundation
role: symbol
role_heading: Type Alias
path: foundation/nsuseractivitypersistentidentifier
---

# NSUserActivityPersistentIdentifier

The type that defines a persistent identifier value for an activity.

## Declaration

```swift
typealias NSUserActivityPersistentIdentifier = String
```

## Discussion

Discussion In Objective-C, NSUserActivity persistent identifiers are a type alias of NSString. In Swift, NSUserActivity persistent identifiers use the NSUserActivityPersistentIdentifier structure.

## See Also

### Describing the activity

- [activityType](foundation/nsuseractivity/activitytype.md)
- [title](foundation/nsuseractivity/title.md)
- [keywords](foundation/nsuseractivity/keywords.md)
- [persistentIdentifier](foundation/nsuseractivity/persistentidentifier.md)
- [contentAttributeSet](foundation/nsuseractivity/contentattributeset.md)