---
title: "Set User Identifier"
slug: "set-user-identifier"
updated: 2026-02-25T14:37:50Z
published: 2026-02-25T14:37:50Z
canonical: "docs.mapp.com/set-user-identifier"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mapp.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Set User Identifier

## Overview

The **Set User Identifier** feature allows you to assign a unique alias to each user, enabling efficient identification and segmentation across multiple devices. This alias serves as a unique identifier that links user data, preferences, and behaviors for a cohesive experience across platforms.

## Use Case Overview

1. **Purpose**:
  - Associate users with a specific identifier like email addresses, system-generated IDs, or other unique data points.
  - Enable consistent user segmentation for personalized engagement and targeted communication.
2. **Benefits**:
  - Link multiple devices (e.g., smartphones, tablets) under a single user profile.
  - Facilitate advanced segmentation by user-specific properties.
  - Enhance reporting accuracy and marketing strategy effectiveness.

## Implementation Details

**Alias Management**

- **Setting an Alias**: Assign a new alias to identify a user across their devices.
- **Retrieving an Alias**: Fetch the alias associated with a specific device.

**Technical Implementation**

1. **Set Alias:**

```java
Appoxee.instance().setAlias("user12345");
```
2. **Get Alias:**

```java
String alias = Appoxee.instance().getAlias();
```

> [!NOTE]
> Keep in mind:
> 
> - The alias is user-specific and shared across all their devices, ensuring a unified user profile.
> - An alias can only be assigned to one user at a time but can be used across multiple devices owned by the user.

## Related

- [Custom Attributes](/custom-attributes.md)
- [Tags](/tags-1.md)
- [Push Notifications](/push-notifications.md)
- [Logout Device](/logout-device.md)