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

# Web SDK Data Tracking Introduction

> Learn about user attribute and event tracking capabilities in the MoEngage Web SDK.

# Overview

MoEngage Web SDK, by default, tracks information for MoEngage default attributes and events. Use additional tracking for best personalization of the message and advance segmentation. Additional tracking is done either for:

# User Attributes

Persistent forever.
For example, email, first name, last name and so on. For more information, refer to [User Attributes](https://www.moengage.com/docs/developer-guide/web-sdk/data-tracking/web-sdk-user-attributes-tracking).

<Note>
  **Note**

  You can not use "moe\_" as a prefix while naming events, event attributes, or user attributes. It is a system prefix and using it might result in periodic blacklisting without prior communication.
</Note>

# Events

Persistent for 60 days unless otherwise defined in your contract.
For example, Order Successful, Started Application and so on.

For more information on MoEngage tracked attributes and events, refer to [Events and Attributes](https://www.moengage.com/docs/user-guide/data/event-data/derived-events-and-attributes) and [Events Tracking](https://www.moengage.com/docs/developer-guide/web-sdk/data-tracking/web-sdk-events-tracking).

For further assistance, please contact your MoEngage Customer Success Manager (CSM) or the Support team.