---
source_url: https://www.pubnub.com/docs/general/resources/migration-guides/objects-v2-migration
title: App Context Migration Guide
updated_at: 2026-06-04T11:10:29.019Z
---

> Documentation Index
> For a curated overview of PubNub documentation, see: https://www.pubnub.com/docs/llms.txt
> For the full list of all documentation pages, see: https://www.pubnub.com/docs/llms-full.txt


# App Context Migration Guide

App Context (formerly Objects v2) provides easy‑to‑use, serverless storage for metadata on users, channels, and memberships. You don’t need to run an external database. Use it to attach properties to users and channels and retrieve them any time to deliver richer experiences.

With App Context, PubNub simplified and streamlined the service to integrate with core capabilities. Use this guide to migrate if you currently use Objects v1.

:::note Objects v1 deprecation
Objects v1 is not supported anymore. If you haven't migrated to App Context now, we strongly suggest that you do that.
:::

## What’s new in App Context

App Context brings consistent SDK methods, a simplified event format, and updated REST APIs. App Context currently doesn’t support authorization using [Access Manager](https://www.pubnub.com/docs/general/security/access-control).

**Spaces replaced with channels.** App Context replaces the concept of spaces with channels. You can use channels as ephemeral identifiers, or optionally store channel metadata.

**Better ties to other services.** SDK methods integrate with existing services and reuse the UUID defined in your instance. You don’t need to specify a separate user ID in each operation.

**User and channel metadata is optional.** You don’t need to store user or channel metadata in PubNub to create memberships. You can keep user data in external systems.

## Migrating your code

To migrate to App Context, upgrade your SDK and update your code to use the new [SDK methods](#new-sdk-methods) and [event format](#new-event-format). See [Migrating your data](#migrating-your-data) if you want to move existing data to the new database.

### New SDK methods

The following tables show old‑to‑new SDK methods using the [JavaScript SDK](https://www.pubnub.com/docs/sdks/javascript/api-reference/objects) as an example. Other SDKs may vary slightly in naming.

#### User management methods

| Old SDK Method | New SDK Method | Description |
| --- | --- | --- |
| createUser | setUUIDMetadata | Sets or updates a user's metadata |
| updateUser | setUUIDMetadata | Sets or updates a user's metadata |
| deleteUser | removeUUIDMetadata | Removes a user's metadata |
| getUser | getUUIDMetadata | Retrieves a user's metadata |
| getUsers | getAllUUIDMetadata | Retrieves metadata for all users |

#### Channel management methods

| Old SDK Method | New SDK Method | Description |
| --- | --- | --- |
| createSpace | setChannelMetadata | Sets or updates a channel's metadata |
| updateSpace | setChannelMetadata | Sets or updates a channel's metadata |
| deleteSpace | removeChannelMetadata | Removes a channel's metadata |
| getSpace | getChannelMetadata | Retrieves a channel's metadata |
| getSpaces | getAllChannelMetadata | Retrieves metadata for all channels |

#### Membership management methods

| Old SDK Method | New SDK Method | Description |
| --- | --- | --- |
| join | setMemberships | Associates a user with one or more channels |
| leave | removeMemberships | Removes a user's association with one or more channels |
| getMemberships | getMemberships | Retrieves a user's memberships |
| addMembers | setChannelMembers | Adds (or updates) one or more users to a channel |
| removeMembers | removeChannelMembers | Removes one or more users from a channel |
| getMembers | getChannelMembers | Retrieves a channel's members |

The `updateMemberships` and `updateMembers` methods have been removed.

### New event format

PubNub triggers events when object data is set, updated, or removed. Setting data to the same value does not trigger an event. Clients receive events in real time and can update the UI accordingly.

With App Context, you receive events in a single format and can use one listener for all App Context events.

:::note User ID / UUID
User ID is also referred to as **UUID/uuid** in some APIs and server responses but **holds the value** of the **userId** parameter you [set during initialization](https://www.pubnub.com/docs/general/setup/users-and-devices#set-the-user-id).
:::

The following JavaScript code adds an App Context listener:

```javascript
pubnub.addListener({
  objects: (o) => {
    var channel = o.channel; // The channel
    var channelGroup = o.subscription; // The channel group
    var timetoken = o.timetoken; // The event timetoken
    var publisher = o.publisher; // The User ID that made the call
    var event = o.message.event; // The event (set or delete) that occurred
    var type = o.message.type; // The type of metadata involved
    var data = o.message.data; // The associated event data
  }
});
```

The following events are defined:

| Event | When is it fired? |
| --- | --- |
| User Metadata Set | Metadata is set for a user |
| User Metadata Deleted | Metadata is deleted for a user |
| Channel Metadata Set | Metadata is set for a channel |
| Channel Metadata Deleted | Metadata is deleted for a channel |
| User Added to Channel | A membership record is created or updated between a user and a channel |
| User Removed from Channel | A membership record is removed between a user and a channel |

All App Context events use the following format:

```javascript
{
  channel: string,
  message: {
     event: string,
     type: string,
     data: object
  }
  subscription: string,
  timetoken: number
}
```

The fields are defined as follows:

* **event** indicates *what* happened, and can be `set` or `delete`
* **type** indicates *where* the event happened, and can be `uuid`, `channel`, or `membership`
* **data** contains event-specific information

## Migrating your data

If you use Objects v1 today, you can continue with SDK versions that still support it.

When you upgrade SDKs to App Context, your data is not migrated automatically. If you want to retain your data, [PubNub Support](https://support.pubnub.com) will help migrate your objects data. Open a support ticket and include the Subscribe key from the [Admin Portal](https://admin.pubnub.com).

There is no charge for data migration. After migration, data is no longer accessible from Objects v1 SDK methods or REST APIs. Most SDKs that support App Context do not support Objects v1.

## REST API endpoints

Please refer to the REST API documentation (App Context for [Users](https://www.pubnub.com/docs/sdks/rest-api/app-context-user-introduction), [Channels](https://www.pubnub.com/docs/sdks/rest-api/app-context-channel-introduction), [Memberships](https://www.pubnub.com/docs/sdks/rest-api/app-context-membership-introduction)) for the new `/v2/objects` REST API endpoints.

## Terms in this document

* **PubNub** - PubNub is a real-time messaging platform that provides APIs and SDKs for building scalable applications. It handles the complex infrastructure of real-time communication, including: Message delivery and persistence, Presence detection, Access control, Push notifications, File sharing, Serverless processing with Functions and Events & Actions, Analytics and monitoring with BizOps Workspace, AI-powered insights with Illuminate.