DataSync API for JavaScript SDK

DataSync is PubNub's data layer for storing application state (users, channels, memberships, and any custom object type) and keeping every connected client current through real-time events. Use it to model the objects your application works with and to react the moment they change.

DataSync is the successor to App Context.

DataSync entities and SDK entities are different things

This page is about DataSync entities, the records the service stores and treats as the source of truth for your application state. They are created and read through the pubnub.dataSync.* methods documented here.

An SDK entity is a local client-side handle such as pubnub.channel('room-1'). It carries no stored state of its own, it just gives you a scoped surface for subscribing and calling APIs. Refer to SDK entities in Publish and subscribe.

The two meet in the DataSync SDK entities: SDK entities whose only job is to subscribe to a DataSync object's real-time updates.

The classes that your objects conform to (their types and schemas) are defined through the Admin API or the Admin Portal, not through this SDK:

• Entity classes, which back users, channels, and custom entities: list, read, create, replace, and delete. Partial updates aren't implemented; replace the complete class version instead.
• Relationship classes, which back memberships and custom relationships: list, read, create, replace, and delete.

A class definition is what decides, for every object of that class, which payload fields are filterable and sortable, which projection each field belongs to, and how long the object lives before it expires. Refer to managing classes for more information.

Every response includes the HTTP status. The remove* methods return the status on its own, every other method adds a data key holding the object, or the array of objects for a list method, and can add a links object with the HATEOAS URLs the service provides (self, and next where it applies). A stored object carries its free-form status and its expiresAt auto-deletion timestamp (ISO 8601) whenever those are set on it.

Authorization

Every DataSync request must be authorized with a token or signature. A request with no credential fails with a 401; an invalid credential or a credential that doesn't permit the operation fails with a 403.

Pagination

DataSync pagination is forward-only. There is no previous-page cursor, and no prev_cursor, has_prev, or links.prev in any response. To revisit an earlier page, page from the start again.

All list methods (getUsers, getChannels, getMemberships, getEntities, and getRelationships) accept cursor and limit (default 20, max 100) and can return a meta object with has_next, next_cursor, and limit. The meta object is optional, so guard the access when you read it, for example response.meta?.next_cursor.

To page forward, pass the returned next_cursor back as cursor on the next call, and stop when has_next is false. next_cursor is null on the last page. Refer to sorting and pagination for details.

Filtering and sorting

All list methods accept two mutually exclusive filter parameters, filter and filterFast. The SDK sends whatever you pass, so a call that carries both reaches the server and fails there with a 400.

Parameter	Consistency	Properties it can read	Expression complexity
filterFast	Strongly consistent, reflects the latest writes	Filtering mode simple or full	Up to 10 conditions by default (raisable per keyset)
filter	Eventually consistent, results can briefly lag writes	Filtering mode full only	Full expression language

Reach for filterFast when the query has to see an object you just wrote, and for filter when you need the full expression language over a full-indexed property.

danger

filter is not the strongly consistent one

The two names read the wrong way round if you assume filter is the basic option. filterFast is the strongly consistent, limited one. filter is the richer, eventually consistent one. Earlier builds of the SDK named these filter and filterAdvanced respectively, so a filter expression written against an older build now runs on the other backing store. Rename filter to filterFast and filterAdvanced to filter when you upgrade.

Both parameters share the same expression language, a string built from a property name, an operator, and a value:

Operators
Comparison	==, !=, <, >, <=, >=
Pattern matching	LIKE (case-insensitive), SLIKE (case-sensitive), ILIKE (case-insensitive, same as LIKE)
Logical	&&, ||, !, and parentheses for grouping

Values are quoted strings, numbers, true, false, or null. Pattern operators (LIKE, SLIKE, ILIKE) apply to string properties only. Reference a property by its name, not its declared path, and only properties declared on the class are filterable. To reach a nested payload property, declare it as a class property first, then filter by that property's name, for example 'price < 100' for a product class that declares price.

Some examples:

1filterFast: 'price < 100'                              // strongly consistent, single condition
2filterFast: '(price < 100 && stock > 0) || price > 500' // strongly consistent, grouped conditions
3filter: 'name LIKE "*sneaker*"'                        // eventually consistent, needs filtering mode "full"
4filter: '!(status == "discontinued")'                  // eventually consistent, negated condition

Both parameters otherwise only work over properties declared on the class. The built-in fields id, createdAt, and updatedAt are always filterable without declaring them on the class. status is too, unless the class redeclares /status scoped to projections your token cannot fully reach. Refer to filtering for the two filtering tiers, and property definitions for how properties are declared.

Use sort to order results. Pass an object mapping each field to a direction. A key's value is 'asc', 'desc', or null to apply the service default (ascending). Map multiple fields to sort by more than one, evaluated in the order the keys appear:

1sort: { price: 'desc' }                        // single field, descending
2sort: { type: 'asc', price: 'desc' }           // type first, then price within each type
3sort: { createdAt: null }                      // explicit service default (ascending)

sort also accepts a raw string, which the SDK passes through unchanged. List the fields separated by commas, each a property name optionally suffixed with :asc or :desc. A bare name sorts ascending:

1sort: 'price:desc'                             // single field, descending
2sort: 'type,price:desc'                        // type ascending, then price descending
3sort: 'createdAt:asc'                          // explicit ascending

The +field and -field prefixes are not accepted. Only properties declared on the class with a filtering mode other than none can be sorted on when sorting alone or alongside filterFast. Sorting alongside filter additionally requires the field to be declared full. The built-in fields id, createdAt, and updatedAt are always sortable without declaring them on the class. status is too, unless the class redeclares /status scoped to projections your token cannot fully reach.

Concurrency (ETag)

Every stored object carries an eTag. To guard against concurrent writes, pass the eTag you read earlier as ifMatchesEtag on set*, update*, and remove*. The SDK sends it as the If-Match request header.

If the server-side value has changed in the meantime, the operation fails with a 412, and you should re-read the object and retry. Refer to optimistic concurrency with ETags for details.

Partial updates

The update* methods apply a partial update using JSON Patch (RFC 6902). They accept add, replace, and test (JSON Pointer key/value maps), remove (an array of JSON Pointers), and move and copy (arrays of { from, path } JSON Pointer pairs). Each path is a full JSON Pointer (RFC 6901) and is sent as you write it. The SDK does not add a /payload prefix. To target a field inside payload, include the prefix yourself, for example replace: { '/payload/price': 79.99 }. To target a top-level field, use a pointer from the document root, for example replace: { '/status': 'active' }.

Refer to partial update for details.

Correct patch forms:

1add: { '/payload/tags/0': 'featured' }                 // adds a value inside payload.tags
2replace: { '/payload/price': 79.99 }                   // replaces payload.price
3remove: ['/payload/tempFlag', '/payload/legacy/field'] // removes payload.tempFlag and payload.legacy.field
4move: [{ from: '/payload/legacyName', path: '/payload/displayName' }]
5copy: [{ from: '/payload/displayName', path: '/payload/previousName' }]
6test: { '/status': 'active' }                          // fails the patch if status is not "active"

Paths address the object's stored property names, the same keys that come back in responses. The class version is entityClassVersion on users, channels, and entities, and relationshipClassVersion on memberships and relationships. The fields set at creation cannot be patched: entityClass and entityClassLevel on users, channels, and entities, relationshipClass, entityAId, and entityBId on relationships, and userId and channelId on memberships.

At least one of add, replace, remove, move, copy, or test must be provided, and it must be non-empty. An empty object or array does not count. The SDK checks this before it sends anything and throws a PubNubError if nothing is provided.

Expiry (TTL)

An object's expiresAt is computed once when the object is created, and updates never refresh it. The value is the creation time plus the class TTL, rounded up to the start of the next whole UTC day, so it rarely lands exactly one TTL from the moment you wrote the object.

Entity classes you create default to a 31-day TTL, while the built-in Global User and Channel classes use 30 days. TTL cannot be disabled. A relationship expires at the earlier expiry time of the two entities it links, fixed when the relationship is created.

Refer to data expiry for details.

Supported and recommended asynchronous patterns

PubNub supports Callbacks, Promises, and Async/Await for asynchronous JS operations. The recommended pattern is Async/Await and all sample requests in this document are based on it. This pattern returns a status only on detecting an error. To receive the error status, you must add the try...catch syntax to your code.

Requires Access Manager

DataSync requires that the Access Manager add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.

Users

Users are built-in objects. There are no top-level name or email fields, all application data lives in the free-form payload. Refer to users for the concept.

A user is an entity of the built-in User entity class, which the service provides at the Global class level. To give your users their own declared, filterable properties, define a subclass of User with Create a new entity class and pass its name as class.

Create user

Creates a user. Supply an id to control the identifier, or omit it to let the server generate one.

Method(s)

1pubnub.dataSync.createUser({
2    id: string,
3    class: string,
4    classLevel: string,
5    data: { classVersion: number, status: string, payload: object },
6}): Promise<DataSync.CreateUserResponse>

* required

Parameter	Description
id Type: string Default: server-generated	User identifier. Omit to let the server generate a UUID. Max 255 characters.
class Type: string Default: User	Name of the entity class this user belongs to. Must be User or one of its subclasses. Set at creation and immutable afterward.
classLevel Type: string Default: service default	Class hierarchy level of class, either Global for a class the service provides or SubKey for one defined on your key set. Set at creation and immutable afterward.
data * Type: object Default: n/a	The mutable user data.
> classVersion * Type: number Default: n/a	Version of the user class schema.
> status Type: string Default: n/a	Free-form lifecycle status. Max 100 characters.
> payload Type: object Default: n/a	Free-form JSON object holding your application data.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.createUser({
3        id: 'user-alice',
4        data: {
5            classVersion: 1,
6            payload: { name: 'Alice', type: 'shopper' },
7        },
8    })
9    console.log(response.data)
10} catch (error) {
11    console.log(error.status)
12}

Response

1{
2    "status": 200,
3    "data": {
4        "id": "user-alice",
5        "entityClassVersion": 1,
6        "payload": {
7            "name": "Alice",
8            "type": "shopper"
9        },
10        "createdAt": "2026-07-13T09:00:00.000Z",
11        "updatedAt": "2026-07-13T09:00:00.000Z",
12        "eTag": "AbQdEfGhIjKlMn"
13    }
14}

Get user

Returns a single user by id.

Method(s)

1pubnub.dataSync.getUser({
2    id: string,
3}): Promise<DataSync.GetUserResponse>

* required

Parameter	Description
id * Type: string Default: n/a	User identifier.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.getUser({ id: 'user-alice' })
3    console.log(response.data)
4} catch (error) {
5    console.log(error.status)
6}

Response

1{
2    "status": 200,
3    "data": {
4        "id": "user-alice",
5        "entityClassVersion": 1,
6        "payload": {
7            "name": "Alice",
8            "type": "shopper"
9        },
10        "createdAt": "2026-07-13T09:00:00.000Z",
11        "updatedAt": "2026-07-13T09:00:00.000Z",
12        "eTag": "AbQdEfGhIjKlMn"
13    }
14}

Get all users

Returns a paginated list of users. All parameters are optional, so you can call getUsers() with no arguments, or pass a callback as the only argument. For pagination, filtering, and sorting, refer to sorting and pagination.

Method(s)

1pubnub.dataSync.getUsers({
2    class: string,
3    classVersion: number,
4    classLevel: string,
5    cursor: string,
6    limit: number,
7    filter: string,
8    filterFast: string,
9    sort: object | string,
10}): Promise<DataSync.GetUsersResponse>

* required

Parameter	Description
class Type: string Default: all user classes	Entity class name to filter by. Omit to list users across every user class.
classVersion Type: number Default: all versions	Entity class version to list. Omit to list users across every version of the class.
classLevel Type: string Default: service default	Class hierarchy level of class, either Global for a class the service provides or SubKey for one defined on your key set. Used to disambiguate a class name defined at both levels.
cursor Type: string Default: n/a	Opaque pagination cursor. Omit for the first page.
limit Type: number Default: 20	Maximum number of users per page. Max 100.
filter Type: string Default: n/a	Filter expression evaluated against eventually consistent storage, so results can briefly lag writes. Supports the full expression language, over properties declared with filtering mode full. Cannot be combined with filterFast.
filterFast Type: string Default: n/a	Filter expression evaluated against strongly consistent storage, so it reflects the latest writes. Accepts up to 10 conditions by default (raisable per keyset), over properties declared with filtering mode simple or full. Cannot be combined with filter.
sort Type: object | string Default: n/a	Order results. An object mapping field to 'asc', 'desc', or null (service default), for example { createdAt: 'desc' }, or a comma-separated string such as 'createdAt:desc'.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.getUsers({
3        limit: 20,
4        sort: { createdAt: 'asc' },
5    })
6    console.log(response.data)
7    console.log(response.meta)
8} catch (error) {
9    console.log(error.status)
10}

Response

1{
2    "status": 200,
3    "data": [
4        {
5            "id": "user-alice",
6            "entityClassVersion": 1,
7            "payload": {
8                "name": "Alice",
9                "type": "shopper"
10            },
11            "createdAt": "2026-07-13T09:00:00.000Z",
12            "updatedAt": "2026-07-13T09:00:00.000Z",
13            "eTag": "AbQdEfGhIjKlMn"
14        }
15    ],
16    "meta": {
17        "next_cursor": "b2Zmc2V0PTIw",
18        "has_next": true,
19        "limit": 20
20    }
21}

show all 21 lines

Other examples

Filter with filter

filter runs over properties declared with filtering mode full and is evaluated against eventually consistent storage, so a very recent write may not be matched yet. Reference a declared property by its name, not its path.

1try {
2    const response = await pubnub.dataSync.getUsers({
3        filter: 'name LIKE "*Alice*"',
4    })
5    console.log(response.data)
6} catch (error) {
7    console.log(error.status)
8}

Filter with filterFast

filterFast is evaluated against strongly consistent storage, so it matches an object you just wrote. It runs over properties declared with filtering mode simple or full and accepts up to 10 conditions by default (raisable per keyset). It shares the same expression language as filter, so only one of the two can be sent per call.

1try {
2    const response = await pubnub.dataSync.getUsers({
3        filterFast: 'type == "shopper"',
4    })
5    console.log(response.data)
6} catch (error) {
7    console.log(error.status)
8}

Page through results with cursor

Pass no cursor on the first call. Take meta.next_cursor from the response and pass it back as cursor on the next call. Stop when meta.has_next is false.

1try {
2    let cursor
3    let hasNext = true
4    let page = 0
5

6    while (hasNext) {
7        const response = await pubnub.dataSync.getUsers({
8            filterFast: 'type == "shopper"',
9            limit: 20,
10            cursor,
11        })
12        console.log(`Page ${++page}:`, response.data)
13        cursor = response.meta?.next_cursor
14        hasNext = response.meta?.has_next ?? false
15    }
16} catch (error) {
17    console.log(error.status)
18}

show all 18 lines

Update user

Replaces a user in full (PUT). Send the complete set of fields, any field you omit is cleared. To guard against concurrent writes, pass ifMatchesEtag (see optimistic concurrency with ETags).

Method(s)

1pubnub.dataSync.setUser({
2    id: string,
3    data: { classVersion: number, status: string, payload: object },
4    ifMatchesEtag: string,
5}): Promise<DataSync.SetUserResponse>

* required

Parameter	Description
id * Type: string Default: n/a	User identifier.
data * Type: object Default: n/a	The replacement user data.
> classVersion * Type: number Default: n/a	Version of the user class schema.
> status Type: string Default: n/a	Free-form lifecycle status. Max 100 characters.
> payload Type: object Default: n/a	Free-form JSON object holding your application data.
ifMatchesEtag Type: string Default: n/a	The eTag from a prior read. The update succeeds only if it still matches, otherwise the server returns 412.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.setUser({
3        id: 'user-alice',
4        data: {
5            classVersion: 1,
6            payload: { name: 'Alice B.', type: 'shopper' },
7        },
8        ifMatchesEtag: 'AbQdEfGhIjKlMn',
9    })
10    console.log(response.data)
11} catch (error) {
12    console.log(error.status)
13}

Response

1{
2    "status": 200,
3    "data": {
4        "id": "user-alice",
5        "entityClassVersion": 1,
6        "payload": {
7            "name": "Alice B.",
8            "type": "shopper"
9        },
10        "createdAt": "2026-07-13T09:00:00.000Z",
11        "updatedAt": "2026-07-13T10:15:00.000Z",
12        "eTag": "CdEfGhIjKlMnOp"
13    }
14}

Patch user

Applies a partial update to a user. Paths can target fields inside payload or top-level stored fields. Refer to partial update for the JSON Pointer rules.

Method(s)

1pubnub.dataSync.updateUser({
2    id: string,
3    add: object,
4    replace: object,
5    remove: string[],
6    move: { from: string, path: string }[],
7    copy: { from: string, path: string }[],
8    test: object,
9    ifMatchesEtag: string,
10}): Promise<DataSync.UpdateUserResponse>

* required

Parameter	Description
id * Type: string Default: n/a	User identifier.
add Type: object Default: n/a	Full JSON Pointers mapped to values to add. Provide at least one patch operation.
replace Type: object Default: n/a	Full JSON Pointers mapped to replacement values. Provide at least one patch operation.
remove Type: array Default: n/a	Full JSON Pointers to remove. Provide at least one patch operation.
move Type: array Default: n/a	Array of { from, path } JSON Pointer pairs. The value at from is removed and re-added at path.
copy Type: array Default: n/a	Array of { from, path } JSON Pointer pairs. The value at from is duplicated to path.
test Type: object Default: n/a	Full JSON Pointers mapped to expected values. The patch fails if any value does not match.
ifMatchesEtag Type: string Default: n/a	The eTag from a prior read. The patch succeeds only if it still matches, otherwise the server returns 412.

Use a JSON Pointer that starts with /payload/ to target payload fields, or a root pointer (for example /status) to target a top-level field. At least one of add, replace, remove, move, copy, or test must be provided.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.updateUser({
3        id: 'user-alice',
4        replace: { '/payload/name': 'Alice B.', '/status': 'active' },
5    })
6    console.log(response.data)
7} catch (error) {
8    console.log(error.status)
9}

Response

1{
2    "status": 200,
3    "data": {
4        "id": "user-alice",
5        "entityClassVersion": 1,
6        "status": "active",
7        "payload": {
8            "name": "Alice B.",
9            "type": "shopper"
10        },
11        "createdAt": "2026-07-13T09:00:00.000Z",
12        "updatedAt": "2026-07-13T10:20:00.000Z",
13        "eTag": "EfGhIjKlMnOpQr"
14    }
15}

Remove user

Deletes a user by id.

Method(s)

1pubnub.dataSync.removeUser({
2    id: string,
3    ifMatchesEtag: string,
4}): Promise<DataSync.RemoveUserResponse>

* required

Parameter	Description
id * Type: string Default: n/a	User identifier.
ifMatchesEtag Type: string Default: n/a	The eTag from a prior read. The delete succeeds only if it still matches, otherwise the server returns 412.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.removeUser({ id: 'user-alice' })
3    console.log(response.status)
4} catch (error) {
5    console.log(error.status)
6}

Response

1{
2    "status": 200
3}

Channels

Channels work like users. They have no top-level name field, all application data lives in payload, and they support the same operations. Refer to channels for the concept.

A channel is an entity of the built-in Channel entity class, which the service provides at the Global class level. Subclass it with Create a new entity class to add declared properties, then pass the subclass name as class.

Create channel

Creates a channel. Supply an id to control the identifier, or omit it to let the server generate one.

Method(s)

1pubnub.dataSync.createChannel({
2    id: string,
3    class: string,
4    classLevel: string,
5    data: { classVersion: number, status: string, payload: object },
6}): Promise<DataSync.CreateChannelResponse>

* required

Parameter	Description
id Type: string Default: server-generated	Channel identifier. Omit to let the server generate a UUID. Max 255 characters.
class Type: string Default: Channel	Name of the entity class this channel belongs to. Must be Channel or one of its subclasses. Set at creation and immutable afterward.
classLevel Type: string Default: service default	Class hierarchy level of class, either Global for a class the service provides or SubKey for one defined on your key set. Set at creation and immutable afterward.
data * Type: object Default: n/a	The mutable channel data.
> classVersion * Type: number Default: n/a	Version of the channel class schema.
> status Type: string Default: n/a	Free-form lifecycle status. Max 100 characters.
> payload Type: object Default: n/a	Free-form JSON object holding your application data.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.createChannel({
3        id: 'channel-summer-sale',
4        data: {
5            classVersion: 1,
6            payload: { name: 'Summer Sale', type: 'promotion' },
7        },
8    })
9    console.log(response.data)
10} catch (error) {
11    console.log(error.status)
12}

Response

1{
2    "status": 200,
3    "data": {
4        "id": "channel-summer-sale",
5        "entityClassVersion": 1,
6        "payload": {
7            "name": "Summer Sale",
8            "type": "promotion"
9        },
10        "createdAt": "2026-07-13T09:05:00.000Z",
11        "updatedAt": "2026-07-13T09:05:00.000Z",
12        "eTag": "GhIjKlMnOpQrSt"
13    }
14}

Get channel

Returns a single channel by id.

Method(s)

1pubnub.dataSync.getChannel({
2    id: string,
3}): Promise<DataSync.GetChannelResponse>

* required

Parameter	Description
id * Type: string Default: n/a	Channel identifier.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.getChannel({ id: 'channel-summer-sale' })
3    console.log(response.data)
4} catch (error) {
5    console.log(error.status)
6}

Response

1{
2    "status": 200,
3    "data": {
4        "id": "channel-summer-sale",
5        "entityClassVersion": 1,
6        "payload": {
7            "name": "Summer Sale",
8            "type": "promotion"
9        },
10        "createdAt": "2026-07-13T09:05:00.000Z",
11        "updatedAt": "2026-07-13T09:05:00.000Z",
12        "eTag": "GhIjKlMnOpQrSt"
13    }
14}

Get all channels

Returns a paginated list of channels. All parameters are optional, so you can call getChannels() with no arguments, or pass a callback as the only argument. For pagination, filtering, and sorting, refer to sorting and pagination.

Method(s)

1pubnub.dataSync.getChannels({
2    class: string,
3    classVersion: number,
4    classLevel: string,
5    cursor: string,
6    limit: number,
7    filter: string,
8    filterFast: string,
9    sort: object | string,
10}): Promise<DataSync.GetChannelsResponse>

* required

Parameter	Description
class Type: string Default: all channel classes	Entity class name to filter by. Omit to list channels across every channel class.
classVersion Type: number Default: all versions	Entity class version to list. Omit to list channels across every version of the class.
classLevel Type: string Default: service default	Class hierarchy level of class, either Global for a class the service provides or SubKey for one defined on your key set. Used to disambiguate a class name defined at both levels.
cursor Type: string Default: n/a	Opaque pagination cursor. Omit for the first page.
limit Type: number Default: 20	Maximum number of channels per page. Max 100.
filter Type: string Default: n/a	Filter expression evaluated against eventually consistent storage, so results can briefly lag writes. Supports the full expression language, over properties declared with filtering mode full. Cannot be combined with filterFast.
filterFast Type: string Default: n/a	Filter expression evaluated against strongly consistent storage, so it reflects the latest writes. Accepts up to 10 conditions by default (raisable per keyset), over properties declared with filtering mode simple or full. Cannot be combined with filter.
sort Type: object | string Default: n/a	Order results. An object mapping field to 'asc', 'desc', or null (service default), or a comma-separated string such as 'createdAt:desc'.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.getChannels({ limit: 20 })
3    console.log(response.data)
4    console.log(response.meta)
5} catch (error) {
6    console.log(error.status)
7}

Response

1{
2    "status": 200,
3    "data": [
4        {
5            "id": "channel-summer-sale",
6            "entityClassVersion": 1,
7            "payload": {
8                "name": "Summer Sale",
9                "type": "promotion"
10            },
11            "createdAt": "2026-07-13T09:05:00.000Z",
12            "updatedAt": "2026-07-13T09:05:00.000Z",
13            "eTag": "GhIjKlMnOpQrSt"
14        }
15    ],
16    "meta": {
17        "next_cursor": null,
18        "has_next": false,
19        "limit": 20
20    }
21}

show all 21 lines

Other examples

Filter with filter

filter runs over properties declared with filtering mode full and is evaluated against eventually consistent storage, so a very recent write may not be matched yet. Reference a declared property by its name, not its path.

1try {
2    const response = await pubnub.dataSync.getChannels({
3        filter: 'name LIKE "*Sale*"',
4    })
5    console.log(response.data)
6} catch (error) {
7    console.log(error.status)
8}

Filter with filterFast

filterFast is evaluated against strongly consistent storage, so it matches an object you just wrote. It runs over properties declared with filtering mode simple or full and accepts up to 10 conditions by default (raisable per keyset). It shares the same expression language as filter, so only one of the two can be sent per call.

1try {
2    const response = await pubnub.dataSync.getChannels({
3        filterFast: 'type == "promotion"',
4    })
5    console.log(response.data)
6} catch (error) {
7    console.log(error.status)
8}

Page through results with cursor

Pass no cursor on the first call. Take meta.next_cursor from the response and pass it back as cursor on the next call. Stop when meta.has_next is false.

1try {
2    let cursor
3    let hasNext = true
4    let page = 0
5

6    while (hasNext) {
7        const response = await pubnub.dataSync.getChannels({
8            filterFast: 'type == "promotion"',
9            limit: 20,
10            cursor,
11        })
12        console.log(`Page ${++page}:`, response.data)
13        cursor = response.meta?.next_cursor
14        hasNext = response.meta?.has_next ?? false
15    }
16} catch (error) {
17    console.log(error.status)
18}

show all 18 lines

Update channel

Replaces a channel in full (PUT). Refer to optimistic concurrency with ETags for ifMatchesEtag.

Method(s)

1pubnub.dataSync.setChannel({
2    id: string,
3    data: { classVersion: number, status: string, payload: object },
4    ifMatchesEtag: string,
5}): Promise<DataSync.SetChannelResponse>

* required

Parameter	Description
id * Type: string Default: n/a	Channel identifier.
data * Type: object Default: n/a	The replacement channel data.
> classVersion * Type: number Default: n/a	Version of the channel class schema.
> status Type: string Default: n/a	Free-form lifecycle status. Max 100 characters.
> payload Type: object Default: n/a	Free-form JSON object holding your application data.
ifMatchesEtag Type: string Default: n/a	The eTag from a prior read. The update succeeds only if it still matches, otherwise the server returns 412.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.setChannel({
3        id: 'channel-summer-sale',
4        data: {
5            classVersion: 1,
6            payload: { name: 'Summer Sale 2026', type: 'promotion' },
7        },
8    })
9    console.log(response.data)
10} catch (error) {
11    console.log(error.status)
12}

Response

1{
2    "status": 200,
3    "data": {
4        "id": "channel-summer-sale",
5        "entityClassVersion": 1,
6        "payload": {
7            "name": "Summer Sale 2026",
8            "type": "promotion"
9        },
10        "createdAt": "2026-07-13T09:05:00.000Z",
11        "updatedAt": "2026-07-13T11:00:00.000Z",
12        "eTag": "IjKlMnOpQrStUv"
13    }
14}

Patch channel

Applies a partial update to a channel. Paths can target fields inside payload or top-level stored fields. Refer to partial update for the JSON Pointer rules.

Method(s)

1pubnub.dataSync.updateChannel({
2    id: string,
3    add: object,
4    replace: object,
5    remove: string[],
6    move: { from: string, path: string }[],
7    copy: { from: string, path: string }[],
8    test: object,
9    ifMatchesEtag: string,
10}): Promise<DataSync.UpdateChannelResponse>

* required

Parameter	Description
id * Type: string Default: n/a	Channel identifier.
add Type: object Default: n/a	Full JSON Pointers mapped to values to add. Provide at least one patch operation.
replace Type: object Default: n/a	Full JSON Pointers mapped to replacement values. Provide at least one patch operation.
remove Type: array Default: n/a	Full JSON Pointers to remove. Provide at least one patch operation.
move Type: array Default: n/a	Array of { from, path } JSON Pointer pairs. The value at from is removed and re-added at path.
copy Type: array Default: n/a	Array of { from, path } JSON Pointer pairs. The value at from is duplicated to path.
test Type: object Default: n/a	Full JSON Pointers mapped to expected values. The patch fails if any value does not match.
ifMatchesEtag Type: string Default: n/a	The eTag from a prior read. The patch succeeds only if it still matches, otherwise the server returns 412.

Use a JSON Pointer that starts with /payload/ to target payload fields, or a root pointer (for example /status) to target a top-level field. At least one of add, replace, remove, move, copy, or test must be provided.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.updateChannel({
3        id: 'channel-summer-sale',
4        replace: { '/payload/name': 'Summer Sale 2026' },
5    })
6    console.log(response.data)
7} catch (error) {
8    console.log(error.status)
9}

Response

1{
2    "status": 200,
3    "data": {
4        "id": "channel-summer-sale",
5        "entityClassVersion": 1,
6        "payload": {
7            "name": "Summer Sale 2026",
8            "type": "promotion"
9        },
10        "createdAt": "2026-07-13T09:05:00.000Z",
11        "updatedAt": "2026-07-13T11:05:00.000Z",
12        "eTag": "KlMnOpQrStUvWx"
13    }
14}

Remove channel

Deletes a channel by id.

Method(s)

1pubnub.dataSync.removeChannel({
2    id: string,
3    ifMatchesEtag: string,
4}): Promise<DataSync.RemoveChannelResponse>

* required

Parameter	Description
id * Type: string Default: n/a	Channel identifier.
ifMatchesEtag Type: string Default: n/a	The eTag from a prior read. The delete succeeds only if it still matches, otherwise the server returns 412.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.removeChannel({ id: 'channel-summer-sale' })
3    console.log(response.status)
4} catch (error) {
5    console.log(error.status)
6}

Response

1{
2    "status": 200
3}

Memberships

A membership links a user to a channel and carries its own payload. In the running example, Alice is a member of channel-summer-sale with the payload { "role": "viewer" }. Refer to memberships for the concept.

A membership is a relationship of the built-in Global Membership relationship class, whose two sides are surfaced as channelId and userId. Every membership response includes both relationshipClass and relationshipClassVersion. The class is assigned by the service, so the createMembership and setMembership methods take no class parameter.

Relationship classes don't support inheritance, and only the Global Membership class produces memberships, so relationshipClass is always Membership and relationshipClassVersion is the only part that varies.

Create membership

Creates a membership linking a user to a channel. The userId/channelId pair must be unique for the membership class. A membership that duplicates an existing pair is rejected with a 409.

Method(s)

1pubnub.dataSync.createMembership({
2    id: string,
3    userId: string,
4    channelId: string,
5    data: { classVersion: number, status: string, payload: object },
6}): Promise<DataSync.CreateMembershipResponse>

* required

Parameter	Description
id Type: string Default: server-generated	Membership identifier. Omit to let the server generate a UUID. Max 255 characters.
userId * Type: string Default: n/a	Identifier of the user in the membership.
channelId * Type: string Default: n/a	Identifier of the channel in the membership.
data * Type: object Default: n/a	The mutable membership data.
> classVersion * Type: number Default: n/a	Version of the membership class schema.
> status Type: string Default: n/a	Free-form lifecycle status. Max 100 characters.
> payload Type: object Default: n/a	Free-form JSON object holding your application data.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.createMembership({
3        userId: 'user-alice',
4        channelId: 'channel-summer-sale',
5        data: {
6            classVersion: 1,
7            payload: { role: 'viewer' },
8        },
9    })
10    console.log(response.data)
11} catch (error) {
12    console.log(error.status)
13}

Response

1{
2    "status": 200,
3    "data": {
4        "id": "membership-alice-summer-sale",
5        "channelId": "channel-summer-sale",
6        "userId": "user-alice",
7        "relationshipClass": "Membership",
8        "relationshipClassVersion": 1,
9        "payload": {
10            "role": "viewer"
11        },
12        "createdAt": "2026-07-13T09:10:00.000Z",
13        "updatedAt": "2026-07-13T09:10:00.000Z",
14        "eTag": "MnOpQrStUvWxYz"
15    }
16}

show all 16 lines

Get membership

Returns a single membership by id.

Method(s)

1pubnub.dataSync.getMembership({
2    id: string,
3}): Promise<DataSync.GetMembershipResponse>

* required

Parameter	Description
id * Type: string Default: n/a	Membership identifier.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.getMembership({
3        id: 'membership-alice-summer-sale',
4    })
5    console.log(response.data)
6} catch (error) {
7    console.log(error.status)
8}

Response

1{
2    "status": 200,
3    "data": {
4        "id": "membership-alice-summer-sale",
5        "channelId": "channel-summer-sale",
6        "userId": "user-alice",
7        "relationshipClass": "Membership",
8        "relationshipClassVersion": 1,
9        "payload": {
10            "role": "viewer"
11        },
12        "createdAt": "2026-07-13T09:10:00.000Z",
13        "updatedAt": "2026-07-13T09:10:00.000Z",
14        "eTag": "MnOpQrStUvWxYz"
15    }
16}

show all 16 lines

Get all memberships

Returns a paginated list of memberships. All parameters are optional, so you can call getMemberships() with no arguments, or pass a callback as the only argument. Filter by userId to list a user's memberships or by channelId to list a channel's members. For pagination, filtering, and sorting, refer to sorting and pagination.

Method(s)

1pubnub.dataSync.getMemberships({
2    cursor: string,
3    limit: number,
4    filter: string,
5    filterFast: string,
6    sort: object | string,
7    userId: string,
8    channelId: string,
9    classVersion: number,
10}): Promise<DataSync.GetMembershipsResponse>

* required

Parameter	Description
cursor Type: string Default: n/a	Opaque pagination cursor. Omit for the first page.
limit Type: number Default: 20	Maximum number of memberships per page. Max 100.
filter Type: string Default: n/a	Filter expression evaluated against eventually consistent storage, so results can briefly lag writes. Supports the full expression language, over properties declared with filtering mode full. Cannot be combined with filterFast.
filterFast Type: string Default: n/a	Filter expression evaluated against strongly consistent storage, so it reflects the latest writes. Accepts up to 10 conditions by default (raisable per keyset), over properties declared with filtering mode simple or full. Cannot be combined with filter.
sort Type: object | string Default: n/a	Order results. An object mapping field to 'asc', 'desc', or null (service default), or a comma-separated string such as 'createdAt:desc'.
userId Type: string Default: n/a	List only memberships for this user.
channelId Type: string Default: n/a	List only memberships for this channel.
classVersion Type: number Default: all versions	Membership class version to list. Omit to list memberships across every version of the class.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.getMemberships({
3        userId: 'user-alice',
4        limit: 20,
5    })
6    console.log(response.data)
7    console.log(response.meta)
8} catch (error) {
9    console.log(error.status)
10}

Response

1{
2    "status": 200,
3    "data": [
4        {
5            "id": "membership-alice-summer-sale",
6            "channelId": "channel-summer-sale",
7            "userId": "user-alice",
8            "relationshipClass": "Membership",
9            "relationshipClassVersion": 1,
10            "payload": {
11                "role": "viewer"
12            },
13            "createdAt": "2026-07-13T09:10:00.000Z",
14            "updatedAt": "2026-07-13T09:10:00.000Z",
15            "eTag": "MnOpQrStUvWxYz"
16        }
17    ],
18    "meta": {
19        "next_cursor": null,
20        "has_next": false,
21        "limit": 20
22    }
23}

show all 23 lines

Other examples

List a channel's members with channelId

Pass channelId instead of userId to list the members of a channel rather than a user's memberships.

1try {
2    const response = await pubnub.dataSync.getMemberships({
3        channelId: 'channel-summer-sale',
4        limit: 20,
5    })
6    console.log(response.data)
7} catch (error) {
8    console.log(error.status)
9}

Filter with filter

filter runs over properties declared with filtering mode full and is evaluated against eventually consistent storage, so a very recent write may not be matched yet. Reference a declared property by its name, not its path.

1try {
2    const response = await pubnub.dataSync.getMemberships({
3        userId: 'user-alice',
4        filter: 'role LIKE "*mod*"',
5    })
6    console.log(response.data)
7} catch (error) {
8    console.log(error.status)
9}

Filter with filterFast

filterFast is evaluated against strongly consistent storage, so it matches an object you just wrote. It runs over properties declared with filtering mode simple or full and accepts up to 10 conditions by default (raisable per keyset). It shares the same expression language as filter, so only one of the two can be sent per call.

1try {
2    const response = await pubnub.dataSync.getMemberships({
3        channelId: 'channel-summer-sale',
4        filterFast: 'role == "viewer"',
5    })
6    console.log(response.data)
7} catch (error) {
8    console.log(error.status)
9}

Page through results with cursor

Pass no cursor on the first call. Take meta.next_cursor from the response and pass it back as cursor on the next call. Stop when meta.has_next is false.

1try {
2    let cursor
3    let hasNext = true
4    let page = 0
5

6    while (hasNext) {
7        const response = await pubnub.dataSync.getMemberships({
8            userId: 'user-alice',
9            limit: 20,
10            cursor,
11        })
12        console.log(`Page ${++page}:`, response.data)
13        cursor = response.meta?.next_cursor
14        hasNext = response.meta?.has_next ?? false
15    }
16} catch (error) {
17    console.log(error.status)
18}

show all 18 lines

Update membership

Replaces a membership in full (PUT). Resend userId, channelId, and classVersion along with the fields you want to keep. For a partial update, use Patch membership. Refer to optimistic concurrency with ETags for ifMatchesEtag.

Method(s)

1pubnub.dataSync.setMembership({
2    id: string,
3    userId: string,
4    channelId: string,
5    data: { classVersion: number, status: string, payload: object },
6    ifMatchesEtag: string,
7}): Promise<DataSync.SetMembershipResponse>

* required

Parameter	Description
id * Type: string Default: n/a	Membership identifier.
userId * Type: string Default: n/a	Identifier of the user in the membership.
channelId * Type: string Default: n/a	Identifier of the channel in the membership.
data * Type: object Default: n/a	The replacement membership data.
> classVersion * Type: number Default: n/a	Version of the membership class schema.
> status Type: string Default: n/a	Free-form lifecycle status. Max 100 characters.
> payload Type: object Default: n/a	Free-form JSON object holding your application data.
ifMatchesEtag Type: string Default: n/a	The eTag from a prior read. The update succeeds only if it still matches, otherwise the server returns 412.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.setMembership({
3        id: 'membership-alice-summer-sale',
4        userId: 'user-alice',
5        channelId: 'channel-summer-sale',
6        data: {
7            classVersion: 1,
8            payload: { role: 'moderator' },
9        },
10    })
11    console.log(response.data)
12} catch (error) {
13    console.log(error.status)
14}

Response

1{
2    "status": 200,
3    "data": {
4        "id": "membership-alice-summer-sale",
5        "channelId": "channel-summer-sale",
6        "userId": "user-alice",
7        "relationshipClass": "Membership",
8        "relationshipClassVersion": 1,
9        "payload": {
10            "role": "moderator"
11        },
12        "createdAt": "2026-07-13T09:10:00.000Z",
13        "updatedAt": "2026-07-13T12:00:00.000Z",
14        "eTag": "OpQrStUvWxYzAb"
15    }
16}

show all 16 lines

Patch membership

Applies a partial update to a membership. Paths can target fields inside payload or top-level stored fields. Refer to partial update for the JSON Pointer rules.

Method(s)

1pubnub.dataSync.updateMembership({
2    id: string,
3    add: object,
4    replace: object,
5    remove: string[],
6    move: { from: string, path: string }[],
7    copy: { from: string, path: string }[],
8    test: object,
9    ifMatchesEtag: string,
10}): Promise<DataSync.UpdateMembershipResponse>

* required

Parameter	Description
id * Type: string Default: n/a	Membership identifier.
add Type: object Default: n/a	Full JSON Pointers mapped to values to add. Provide at least one patch operation.
replace Type: object Default: n/a	Full JSON Pointers mapped to replacement values. Provide at least one patch operation.
remove Type: array Default: n/a	Full JSON Pointers to remove. Provide at least one patch operation.
move Type: array Default: n/a	Array of { from, path } JSON Pointer pairs. The value at from is removed and re-added at path.
copy Type: array Default: n/a	Array of { from, path } JSON Pointer pairs. The value at from is duplicated to path.
test Type: object Default: n/a	Full JSON Pointers mapped to expected values. The patch fails if any value does not match.
ifMatchesEtag Type: string Default: n/a	The eTag from a prior read. The patch succeeds only if it still matches, otherwise the server returns 412.

Use a JSON Pointer that starts with /payload/ to target payload fields, or a root pointer (for example /status) to target a top-level field. At least one of add, replace, remove, move, copy, or test must be provided.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.updateMembership({
3        id: 'membership-alice-summer-sale',
4        replace: { '/payload/role': 'moderator' },
5    })
6    console.log(response.data)
7} catch (error) {
8    console.log(error.status)
9}

Response

1{
2    "status": 200,
3    "data": {
4        "id": "membership-alice-summer-sale",
5        "channelId": "channel-summer-sale",
6        "userId": "user-alice",
7        "relationshipClass": "Membership",
8        "relationshipClassVersion": 1,
9        "payload": {
10            "role": "moderator"
11        },
12        "createdAt": "2026-07-13T09:10:00.000Z",
13        "updatedAt": "2026-07-13T12:05:00.000Z",
14        "eTag": "QrStUvWxYzAbCd"
15    }
16}

show all 16 lines

Remove membership

Deletes a membership by id.

Method(s)

1pubnub.dataSync.removeMembership({
2    id: string,
3    ifMatchesEtag: string,
4}): Promise<DataSync.RemoveMembershipResponse>

* required

Parameter	Description
id * Type: string Default: n/a	Membership identifier.
ifMatchesEtag Type: string Default: n/a	The eTag from a prior read. The delete succeeds only if it still matches, otherwise the server returns 412.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.removeMembership({
3        id: 'membership-alice-summer-sale',
4    })
5    console.log(response.status)
6} catch (error) {
7    console.log(error.status)
8}

Response

1{
2    "status": 200
3}

Entities

Entities are instances of the custom entity classes you define on your key set. In the running example, product is a class and product-sneaker-42 is an instance. Use Create a new entity class to declare a class, and Get entity class by ID to read the property, filtering, and projection declarations that govern its instances.

Entity classes can extend one another. Listing a class also returns the entities of its subclasses, so getEntities({ class: 'product' }) returns every product plus every instance of a class that extends product.

Create entity

Creates an entity of a given class and version.

Method(s)

1pubnub.dataSync.createEntity({
2    id: string,
3    class: string,
4    classLevel: string,
5    data: { classVersion: number, status: string, payload: object },
6}): Promise<DataSync.CreateEntityResponse>

* required

Parameter	Description
id Type: string Default: server-generated	Entity identifier. Omit to let the server generate a UUID. Max 255 characters.
class * Type: string Default: n/a	Name of the entity class this instance belongs to. Set at creation and immutable afterward.
classLevel Type: string Default: service default	Class hierarchy level of class, either Global for a class the service provides or SubKey for one defined on your key set. Set at creation and immutable afterward.
data * Type: object Default: n/a	The mutable entity data.
> classVersion * Type: number Default: n/a	Version of the entity class schema.
> status Type: string Default: n/a	Free-form lifecycle status. Max 100 characters.
> payload Type: object Default: n/a	Free-form JSON object holding your application data.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.createEntity({
3        id: 'product-sneaker-42',
4        class: 'product',
5        data: {
6            classVersion: 1,
7            payload: { name: 'Retro Sneaker', price: 89.99, stock: 12 },
8        },
9    })
10    console.log(response.data)
11} catch (error) {
12    console.log(error.status)
13}

Response

1{
2    "status": 200,
3    "data": {
4        "id": "product-sneaker-42",
5        "entityClass": "product",
6        "entityClassVersion": 1,
7        "payload": {
8            "name": "Retro Sneaker",
9            "price": 89.99,
10            "stock": 12
11        },
12        "createdAt": "2026-07-13T09:15:00.000Z",
13        "updatedAt": "2026-07-13T09:15:00.000Z",
14        "eTag": "QrStUvWxYzAbCd"
15    }
16}

show all 16 lines

Get entity

Returns a single entity by id.

Method(s)

1pubnub.dataSync.getEntity({
2    id: string,
3}): Promise<DataSync.GetEntityResponse>

* required

Parameter	Description
id * Type: string Default: n/a	Entity identifier.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.getEntity({ id: 'product-sneaker-42' })
3    console.log(response.data)
4} catch (error) {
5    console.log(error.status)
6}

Response

1{
2    "status": 200,
3    "data": {
4        "id": "product-sneaker-42",
5        "entityClass": "product",
6        "entityClassVersion": 1,
7        "payload": {
8            "name": "Retro Sneaker",
9            "price": 89.99,
10            "stock": 12
11        },
12        "createdAt": "2026-07-13T09:15:00.000Z",
13        "updatedAt": "2026-07-13T09:15:00.000Z",
14        "eTag": "QrStUvWxYzAbCd"
15    }
16}

show all 16 lines

Get all entities

Returns a paginated list of entities within a class. The class parameter is required, entities are always listed within the context of their class. For pagination, filtering, and sorting, refer to sorting and pagination.

Method(s)

1pubnub.dataSync.getEntities({
2    class: string,
3    classVersion: number,
4    classLevel: string,
5    cursor: string,
6    limit: number,
7    filter: string,
8    filterFast: string,
9    sort: object | string,
10}): Promise<DataSync.GetEntitiesResponse>

* required

Parameter	Description
class * Type: string Default: n/a	Name of the entity class to list. This parameter is required.
classVersion Type: number Default: all versions	Entity class version to list. Omit to list entities across every version of the class.
classLevel Type: string Default: service default	Class hierarchy level of class, either Global for a class the service provides or SubKey for one defined on your key set. Used to disambiguate a class name defined at both levels.
cursor Type: string Default: n/a	Opaque pagination cursor. Omit for the first page.
limit Type: number Default: 20	Maximum number of entities per page. Max 100.
filter Type: string Default: n/a	Filter expression evaluated against eventually consistent storage, so results can briefly lag writes. Supports the full expression language, over properties declared with filtering mode full. Cannot be combined with filterFast.
filterFast Type: string Default: n/a	Filter expression evaluated against strongly consistent storage, so it reflects the latest writes. Accepts up to 10 conditions by default (raisable per keyset), over properties declared with filtering mode simple or full. Cannot be combined with filter.
sort Type: object | string Default: n/a	Order results. An object mapping field to 'asc', 'desc', or null (service default), or a comma-separated string such as 'createdAt:desc'.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.getEntities({
3        class: 'product',
4        sort: { price: 'desc' },
5        limit: 20,
6    })
7    console.log(response.data)
8    console.log(response.meta)
9} catch (error) {
10    console.log(error.status)
11}

Response

1{
2    "status": 200,
3    "data": [
4        {
5            "id": "product-sneaker-42",
6            "entityClass": "product",
7            "entityClassVersion": 1,
8            "payload": {
9                "name": "Retro Sneaker",
10                "price": 89.99,
11                "stock": 12
12            },
13            "createdAt": "2026-07-13T09:15:00.000Z",
14            "updatedAt": "2026-07-13T09:15:00.000Z",
15            "eTag": "QrStUvWxYzAbCd"
16        }
17    ],
18    "meta": {
19        "next_cursor": null,
20        "has_next": false,
21        "limit": 20
22    }
23}

show all 23 lines

Other examples

Filter with filter

filter runs over properties declared with filtering mode full and is evaluated against eventually consistent storage, so a very recent write may not be matched yet. Reference a declared property by its name (not its path), and combine conditions with && and ||.

1try {
2    const response = await pubnub.dataSync.getEntities({
3        class: 'product',
4        filter: 'name LIKE "*sneaker*" && !(status == "discontinued")',
5    })
6    console.log(response.data)
7} catch (error) {
8    console.log(error.status)
9}

Filter with filterFast

filterFast is evaluated against strongly consistent storage, so it matches an object you just wrote. It runs over properties declared with filtering mode simple or full and accepts up to 10 conditions by default (raisable per keyset). It shares the same expression language as filter, so only one of the two can be sent per call.

1try {
2    const response = await pubnub.dataSync.getEntities({
3        class: 'product',
4        filterFast: 'price < 100 && stock > 0',
5    })
6    console.log(response.data)
7} catch (error) {
8    console.log(error.status)
9}

Page through results with cursor

Pass no cursor on the first call. Take meta.next_cursor from the response and pass it back as cursor on the next call. Stop when meta.has_next is false.

1try {
2    let cursor
3    let hasNext = true
4    let page = 0
5

6    while (hasNext) {
7        const response = await pubnub.dataSync.getEntities({
8            class: 'product',
9            filterFast: 'price < 100',
10            limit: 20,
11            cursor,
12        })
13        console.log(`Page ${++page}:`, response.data)
14        cursor = response.meta?.next_cursor
15        hasNext = response.meta?.has_next ?? false
16    }
17} catch (error) {
18    console.log(error.status)
19}

show all 19 lines

Update entity

Replaces an entity in full (PUT). The entityClass is immutable after creation and cannot be sent. Refer to optimistic concurrency with ETags for ifMatchesEtag.

Method(s)

1pubnub.dataSync.setEntity({
2    id: string,
3    data: { classVersion: number, status: string, payload: object },
4    ifMatchesEtag: string,
5}): Promise<DataSync.SetEntityResponse>

* required

Parameter	Description
id * Type: string Default: n/a	Entity identifier.
data * Type: object Default: n/a	The replacement entity data. The entity class is immutable and cannot be included.
> classVersion * Type: number Default: n/a	Version of the entity class schema.
> status Type: string Default: n/a	Free-form lifecycle status. Max 100 characters.
> payload Type: object Default: n/a	Free-form JSON object holding your application data.
ifMatchesEtag Type: string Default: n/a	The eTag from a prior read. The update succeeds only if it still matches, otherwise the server returns 412.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.setEntity({
3        id: 'product-sneaker-42',
4        data: {
5            classVersion: 1,
6            payload: { name: 'Retro Sneaker', price: 79.99, stock: 8 },
7        },
8    })
9    console.log(response.data)
10} catch (error) {
11    console.log(error.status)
12}

Response

1{
2    "status": 200,
3    "data": {
4        "id": "product-sneaker-42",
5        "entityClass": "product",
6        "entityClassVersion": 1,
7        "payload": {
8            "name": "Retro Sneaker",
9            "price": 79.99,
10            "stock": 8
11        },
12        "createdAt": "2026-07-13T09:15:00.000Z",
13        "updatedAt": "2026-07-13T13:00:00.000Z",
14        "eTag": "StUvWxYzAbCdEf"
15    }
16}

show all 16 lines

Patch entity

Applies a partial update to an entity. Paths can target fields inside payload or top-level stored fields. Refer to partial update for the JSON Pointer rules.

Method(s)

1pubnub.dataSync.updateEntity({
2    id: string,
3    add: object,
4    replace: object,
5    remove: string[],
6    move: { from: string, path: string }[],
7    copy: { from: string, path: string }[],
8    test: object,
9    ifMatchesEtag: string,
10}): Promise<DataSync.UpdateEntityResponse>

* required

Parameter	Description
id * Type: string Default: n/a	Entity identifier.
add Type: object Default: n/a	Full JSON Pointers mapped to values to add. Provide at least one patch operation.
replace Type: object Default: n/a	Full JSON Pointers mapped to replacement values. Provide at least one patch operation.
remove Type: array Default: n/a	Full JSON Pointers to remove. Provide at least one patch operation.
move Type: array Default: n/a	Array of { from, path } JSON Pointer pairs. The value at from is removed and re-added at path.
copy Type: array Default: n/a	Array of { from, path } JSON Pointer pairs. The value at from is duplicated to path.
test Type: object Default: n/a	Full JSON Pointers mapped to expected values. The patch fails if any value does not match.
ifMatchesEtag Type: string Default: n/a	The eTag from a prior read. The patch succeeds only if it still matches, otherwise the server returns 412.

Use a JSON Pointer that starts with /payload/ to target payload fields, or a root pointer (for example /status) to target a top-level field. At least one of add, replace, remove, move, copy, or test must be provided.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.updateEntity({
3        id: 'product-sneaker-42',
4        replace: { '/payload/price': 79.99 },
5    })
6    console.log(response.data)
7} catch (error) {
8    console.log(error.status)
9}

Response

1{
2    "status": 200,
3    "data": {
4        "id": "product-sneaker-42",
5        "entityClass": "product",
6        "entityClassVersion": 1,
7        "payload": {
8            "name": "Retro Sneaker",
9            "price": 79.99,
10            "stock": 12
11        },
12        "createdAt": "2026-07-13T09:15:00.000Z",
13        "updatedAt": "2026-07-13T13:05:00.000Z",
14        "eTag": "UvWxYzAbCdEfGh"
15    }
16}

show all 16 lines

Other examples

Combine patch operations, and guard the write with ifMatchesEtag

A single updateEntity call can mix add, replace, remove, move, copy, and test. The order you write the keys in does not matter, the SDK always sends the operations in the same order: add, replace, remove, move, copy, and test last. Add ifMatchesEtag (the eTag from a prior read) to reject the patch with a 412 if the entity changed since you read it, instead of silently overwriting a concurrent change.

1try {
2    const response = await pubnub.dataSync.updateEntity({
3        id: 'product-sneaker-42',
4        test: { '/payload/stock': 8 },
5        replace: { '/payload/price': 74.99 },
6        add: { '/payload/tags/0': 'clearance' },
7        remove: ['/payload/legacy/field'],
8        move: [{ from: '/payload/legacyName', path: '/payload/displayName' }],
9        copy: [{ from: '/payload/displayName', path: '/payload/previousName' }],
10        ifMatchesEtag: 'StUvWxYzAbCdEf',
11    })
12    console.log(response.data)
13} catch (error) {
14    console.log(error.status)
15}

Remove entity

Deletes an entity by id.

Method(s)

1pubnub.dataSync.removeEntity({
2    id: string,
3    ifMatchesEtag: string,
4}): Promise<DataSync.RemoveEntityResponse>

* required

Parameter	Description
id * Type: string Default: n/a	Entity identifier.
ifMatchesEtag Type: string Default: n/a	The eTag from a prior read. The delete succeeds only if it still matches, otherwise the server returns 412.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.removeEntity({ id: 'product-sneaker-42' })
3    console.log(response.status)
4} catch (error) {
5    console.log(error.status)
6}

Response

1{
2    "status": 200
3}

Relationships

A relationship links two entities and carries its own payload. In the running example, the ProductOwner relationship links seller-bob to product-sneaker-42.

Relationships are instances of the relationship classes you define on your key set. A relationship class declares the cardinality the service enforces (one-to-one, one-to-many, or many-to-many) and, optionally, which entity class each side must belong to. Use Create a new relationship class to declare a class, and Get relationship class by name and version to read it back.

Create relationship

Creates a relationship between two entities. The relationship class's cardinality (one-to-one, one-to-many, or many-to-many) is enforced on create. A relationship that violates its class's cardinality is rejected with a 409.

Method(s)

1pubnub.dataSync.createRelationship({
2    id: string,
3    class: string,
4    entityAId: string,
5    entityBId: string,
6    data: { classVersion: number, status: string, payload: object },
7}): Promise<DataSync.CreateRelationshipResponse>

* required

Parameter	Description
id Type: string Default: server-generated	Relationship identifier. Omit to let the server generate a UUID. Max 255 characters.
class * Type: string Default: n/a	Name of the relationship class this instance belongs to. Set at creation and immutable afterward.
entityAId * Type: string Default: n/a	Identifier of the first linked entity. Immutable after creation.
entityBId * Type: string Default: n/a	Identifier of the second linked entity. Immutable after creation.
data * Type: object Default: n/a	The mutable relationship data.
> classVersion * Type: number Default: n/a	Version of the relationship class schema.
> status Type: string Default: n/a	Free-form lifecycle status. Max 100 characters.
> payload Type: object Default: n/a	Free-form JSON object holding your application data.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.createRelationship({
3        class: 'ProductOwner',
4        entityAId: 'seller-bob',
5        entityBId: 'product-sneaker-42',
6        data: {
7            classVersion: 1,
8            payload: { since: '2026-07-13' },
9        },
10    })
11    console.log(response.data)
12} catch (error) {
13    console.log(error.status)
14}

Response

1{
2    "status": 200,
3    "data": {
4        "id": "rel-bob-owns-sneaker-42",
5        "entityAId": "seller-bob",
6        "entityBId": "product-sneaker-42",
7        "relationshipClass": "ProductOwner",
8        "relationshipClassVersion": 1,
9        "payload": {
10            "since": "2026-07-13"
11        },
12        "createdAt": "2026-07-13T09:20:00.000Z",
13        "updatedAt": "2026-07-13T09:20:00.000Z",
14        "eTag": "WxYzAbCdEfGhIj"
15    }
16}

show all 16 lines

Get relationship

Returns a single relationship by id.

Method(s)

1pubnub.dataSync.getRelationship({
2    id: string,
3}): Promise<DataSync.GetRelationshipResponse>

* required

Parameter	Description
id * Type: string Default: n/a	Relationship identifier.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.getRelationship({
3        id: 'rel-bob-owns-sneaker-42',
4    })
5    console.log(response.data)
6} catch (error) {
7    console.log(error.status)
8}

Response

1{
2    "status": 200,
3    "data": {
4        "id": "rel-bob-owns-sneaker-42",
5        "entityAId": "seller-bob",
6        "entityBId": "product-sneaker-42",
7        "relationshipClass": "ProductOwner",
8        "relationshipClassVersion": 1,
9        "payload": {
10            "since": "2026-07-13"
11        },
12        "createdAt": "2026-07-13T09:20:00.000Z",
13        "updatedAt": "2026-07-13T09:20:00.000Z",
14        "eTag": "WxYzAbCdEfGhIj"
15    }
16}

show all 16 lines

Get all relationships

Returns a paginated list of relationships within a class. The class parameter is required. Filter by entityAId or entityBId to list a specific entity's links. For pagination, filtering, and sorting, refer to sorting and pagination.

Method(s)

1pubnub.dataSync.getRelationships({
2    class: string,
3    classVersion: number,
4    entityAId: string,
5    entityBId: string,
6    cursor: string,
7    limit: number,
8    filter: string,
9    filterFast: string,
10    sort: object | string,
11}): Promise<DataSync.GetRelationshipsResponse>

* required

Parameter	Description
class * Type: string Default: n/a	Name of the relationship class to list. This parameter is required.
classVersion Type: number Default: all versions	Relationship class version to list. Omit to list relationships across every version of the class.
entityAId Type: string Default: n/a	List only relationships whose first entity is this id.
entityBId Type: string Default: n/a	List only relationships whose second entity is this id.
cursor Type: string Default: n/a	Opaque pagination cursor. Omit for the first page.
limit Type: number Default: 20	Maximum number of relationships per page. Max 100.
filter Type: string Default: n/a	Filter expression evaluated against eventually consistent storage, so results can briefly lag writes. Supports the full expression language, over properties declared with filtering mode full. Cannot be combined with filterFast.
filterFast Type: string Default: n/a	Filter expression evaluated against strongly consistent storage, so it reflects the latest writes. Accepts up to 10 conditions by default (raisable per keyset), over properties declared with filtering mode simple or full. Cannot be combined with filter.
sort Type: object | string Default: n/a	Order results. An object mapping field to 'asc', 'desc', or null (service default), or a comma-separated string such as 'createdAt:desc'.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.getRelationships({
3        class: 'ProductOwner',
4        entityAId: 'seller-bob',
5        limit: 20,
6    })
7    console.log(response.data)
8    console.log(response.meta)
9} catch (error) {
10    console.log(error.status)
11}

Response

1{
2    "status": 200,
3    "data": [
4        {
5            "id": "rel-bob-owns-sneaker-42",
6            "entityAId": "seller-bob",
7            "entityBId": "product-sneaker-42",
8            "relationshipClass": "ProductOwner",
9            "relationshipClassVersion": 1,
10            "payload": {
11                "since": "2026-07-13"
12            },
13            "createdAt": "2026-07-13T09:20:00.000Z",
14            "updatedAt": "2026-07-13T09:20:00.000Z",
15            "eTag": "WxYzAbCdEfGhIj"
16        }
17    ],
18    "meta": {
19        "next_cursor": null,
20        "has_next": false,
21        "limit": 20
22    }
23}

show all 23 lines

Other examples

List an entity's incoming links with entityBId

Pass entityBId instead of entityAId to list relationships where the entity is on the second side of the link.

1try {
2    const response = await pubnub.dataSync.getRelationships({
3        class: 'ProductOwner',
4        entityBId: 'product-sneaker-42',
5        limit: 20,
6    })
7    console.log(response.data)
8} catch (error) {
9    console.log(error.status)
10}

Filter with filter

filter runs over properties declared with filtering mode full and is evaluated against eventually consistent storage, so a very recent write may not be matched yet. Reference a declared property by its name, not its path.

1try {
2    const response = await pubnub.dataSync.getRelationships({
3        class: 'ProductOwner',
4        filter: '!(tier == "platinum")',
5    })
6    console.log(response.data)
7} catch (error) {
8    console.log(error.status)
9}

Filter with filterFast

filterFast is evaluated against strongly consistent storage, so it matches an object you just wrote. It runs over properties declared with filtering mode simple or full and accepts up to 10 conditions by default (raisable per keyset). It shares the same expression language as filter, so only one of the two can be sent per call.

1try {
2    const response = await pubnub.dataSync.getRelationships({
3        class: 'ProductOwner',
4        filterFast: 'tier == "gold"',
5    })
6    console.log(response.data)
7} catch (error) {
8    console.log(error.status)
9}

Page through results with cursor

Pass no cursor on the first call. Take meta.next_cursor from the response and pass it back as cursor on the next call. Stop when meta.has_next is false.

1try {
2    let cursor
3    let hasNext = true
4    let page = 0
5

6    while (hasNext) {
7        const response = await pubnub.dataSync.getRelationships({
8            class: 'ProductOwner',
9            entityAId: 'seller-bob',
10            limit: 20,
11            cursor,
12        })
13        console.log(`Page ${++page}:`, response.data)
14        cursor = response.meta?.next_cursor
15        hasNext = response.meta?.has_next ?? false
16    }
17} catch (error) {
18    console.log(error.status)
19}

show all 19 lines

Update relationship

Replaces a relationship in full (PUT). The linked entity ids are immutable, so resend the same entityAId and entityBId. Refer to optimistic concurrency with ETags for ifMatchesEtag.

Method(s)

1pubnub.dataSync.setRelationship({
2    id: string,
3    entityAId: string,
4    entityBId: string,
5    data: { classVersion: number, status: string, payload: object },
6    ifMatchesEtag: string,
7}): Promise<DataSync.SetRelationshipResponse>

* required

Parameter	Description
id * Type: string Default: n/a	Relationship identifier.
entityAId * Type: string Default: n/a	Identifier of the first linked entity. Must match the value set at creation.
entityBId * Type: string Default: n/a	Identifier of the second linked entity. Must match the value set at creation.
data * Type: object Default: n/a	The replacement relationship data. The relationship class is immutable and cannot be included.
> classVersion * Type: number Default: n/a	Version of the relationship class schema.
> status Type: string Default: n/a	Free-form lifecycle status. Max 100 characters.
> payload Type: object Default: n/a	Free-form JSON object holding your application data.
ifMatchesEtag Type: string Default: n/a	The eTag from a prior read. The update succeeds only if it still matches, otherwise the server returns 412.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.setRelationship({
3        id: 'rel-bob-owns-sneaker-42',
4        entityAId: 'seller-bob',
5        entityBId: 'product-sneaker-42',
6        data: {
7            classVersion: 1,
8            payload: { since: '2026-07-13', tier: 'gold' },
9        },
10    })
11    console.log(response.data)
12} catch (error) {
13    console.log(error.status)
14}

Response

1{
2    "status": 200,
3    "data": {
4        "id": "rel-bob-owns-sneaker-42",
5        "entityAId": "seller-bob",
6        "entityBId": "product-sneaker-42",
7        "relationshipClass": "ProductOwner",
8        "relationshipClassVersion": 1,
9        "payload": {
10            "since": "2026-07-13",
11            "tier": "gold"
12        },
13        "createdAt": "2026-07-13T09:20:00.000Z",
14        "updatedAt": "2026-07-13T14:00:00.000Z",
15        "eTag": "YzAbCdEfGhIjKl"
16    }
17}

show all 17 lines

Patch relationship

Applies a partial update to a relationship. Paths can target fields inside payload or top-level stored fields. Refer to partial update for the JSON Pointer rules.

Method(s)

1pubnub.dataSync.updateRelationship({
2    id: string,
3    add: object,
4    replace: object,
5    remove: string[],
6    move: { from: string, path: string }[],
7    copy: { from: string, path: string }[],
8    test: object,
9    ifMatchesEtag: string,
10}): Promise<DataSync.UpdateRelationshipResponse>

* required

Parameter	Description
id * Type: string Default: n/a	Relationship identifier.
add Type: object Default: n/a	Full JSON Pointers mapped to values to add. Provide at least one patch operation.
replace Type: object Default: n/a	Full JSON Pointers mapped to replacement values. Provide at least one patch operation.
remove Type: array Default: n/a	Full JSON Pointers to remove. Provide at least one patch operation.
move Type: array Default: n/a	Array of { from, path } JSON Pointer pairs. The value at from is removed and re-added at path.
copy Type: array Default: n/a	Array of { from, path } JSON Pointer pairs. The value at from is duplicated to path.
test Type: object Default: n/a	Full JSON Pointers mapped to expected values. The patch fails if any value does not match.
ifMatchesEtag Type: string Default: n/a	The eTag from a prior read. The patch succeeds only if it still matches, otherwise the server returns 412.

Use a JSON Pointer that starts with /payload/ to target payload fields, or a root pointer (for example /status) to target a top-level field. At least one of add, replace, remove, move, copy, or test must be provided.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.updateRelationship({
3        id: 'rel-bob-owns-sneaker-42',
4        replace: { '/payload/tier': 'platinum' },
5    })
6    console.log(response.data)
7} catch (error) {
8    console.log(error.status)
9}

Response

1{
2    "status": 200,
3    "data": {
4        "id": "rel-bob-owns-sneaker-42",
5        "entityAId": "seller-bob",
6        "entityBId": "product-sneaker-42",
7        "relationshipClass": "ProductOwner",
8        "relationshipClassVersion": 1,
9        "payload": {
10            "since": "2026-07-13",
11            "tier": "platinum"
12        },
13        "createdAt": "2026-07-13T09:20:00.000Z",
14        "updatedAt": "2026-07-13T14:05:00.000Z",
15        "eTag": "AbCdEfGhIjKlMn"
16    }
17}

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Remove relationship

Deletes a relationship by id.

Method(s)

1pubnub.dataSync.removeRelationship({
2    id: string,
3    ifMatchesEtag: string,
4}): Promise<DataSync.RemoveRelationshipResponse>

* required

Parameter	Description
id * Type: string Default: n/a	Relationship identifier.
ifMatchesEtag Type: string Default: n/a	The eTag from a prior read. The delete succeeds only if it still matches, otherwise the server returns 412.

Sample code

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

1try {
2    const response = await pubnub.dataSync.removeRelationship({
3        id: 'rel-bob-owns-sneaker-42',
4    })
5    console.log(response.status)
6} catch (error) {
7    console.log(error.status)
8}

Response

1{
2    "status": 200
3}

Real-time updates

DataSync objects can publish create, update, and delete events that you receive in real time with a dataSync listener. Create a DataSync SDK entity for the object, subscribe to it, and attach the listener, described in the Add DataSync listener section of Publish and subscribe.

1const subscription = pubnub.dataSyncEntity('product-sneaker-42').subscription()
2subscription.onDataSync = (event) => console.log(event.message.event, event.message.data)
3subscription.subscribe()

Each event names the change in event, identifies the object kind in objectType (user, channel, membership, entity, or relationship), and carries the object state in data. For a delete event, data holds only the id and, when the service reports it, deletedAt.

Where each event is delivered

A relationship or membership change is never delivered on a channel named after the relationship or membership id, only on the ids of the two entities it links. A create for a user, channel, or entity is delivered only on its own id. An update or delete for a user, channel, or entity is also delivered on the id of every entity, user, or channel connected to it by a relationship or membership, in either direction, at the time of the change:

Change to	create delivered on	update / delete delivered on
A user	The user's id	The user's id, plus the id of every entity, user, or channel connected to it by a relationship or membership
A channel	The channel's id	The channel's id, plus the id of every entity, user, or channel connected to it by a relationship or membership
An entity	The entity's id	The entity's id, plus the id of every entity, user, or channel connected to it by a relationship or membership
A membership	Both the userId and the channelId of the membership	Both the userId and the channelId of the membership
A relationship	Both the entityAId and the entityBId of the relationship	Both the entityAId and the entityBId of the relationship

So to see memberships appear and disappear for Alice, observe user-alice rather than the membership id. Unlike entity/user/channel events, a membership or relationship create is delivered on both linked ids too, the same as its update/delete. A client observing both sides of the same link receives the change twice, once per channel. Deduplicate create and update events on data.id and data.updatedAt, and delete events on data.id and data.deletedAt.

Events are off by default and are enabled per class in the Admin Portal. Refer to enabling events for how to turn them on, and receiving events for the listener flow.