---
source_url: https://www.pubnub.com/docs/sdks/rest-api/data-sync-user-introduction
title: DataSync (User) introduction
---

# DataSync (User) introduction

> For AI agents: documentation index at https://www.pubnub.com/llms-full.txt

Users are a built-in DataSync entity class representing the people or devices in your app.

**Note:** For more information, refer to [Users, channels, and memberships](https://www.pubnub.com/docs/data-storage/structured-data/built-in-types.md). These endpoints are the DataSync successor to the App Context user endpoints, which remain available.

### Authorization

Access Manager must be enabled on the keyset, and every DataSync request must carry exactly one credential: either an Access Manager token in `auth`, or a request `signature`. There is no anonymous access.

Supplying neither fails with `401` (`DS-0203`, UNAUTHENTICATED). Supplying both fails with `403` (`DS-0201`, ACCESS_DENIED), as does calling DataSync on a keyset without Access Manager enabled.

Refer to [DataSync access control](https://www.pubnub.com/docs/data-storage/structured-data/access-control.md).