---
title: identifier
framework: uikit
role: symbol
role_heading: Type Property
path: uikit/uitraitdefinition-3572h/identifier
---

# identifier

A unique identifier string for the trait (reverse-DNS format recommended). Allows the trait to be encoded/decoded, and to map both a Swift and Objective-C trait to the same data.

## Declaration

```occ
@property (class, nonatomic, readonly) NSString * identifier;
```

## Mentioned in

Providing data to the view hierarchy with custom traits

## See Also

### Type Properties

- [affectsColorAppearance](uikit/uitraitdefinition-3572h/affectscolorappearance.md)
- [name](uikit/uitraitdefinition-3572h/name.md)