Configuration API for JavaScript SDK

JavaScript complete API reference for building real-time applications on PubNub, including basic usage and sample code.

You must include the PubNub JavaScript SDK in your code before initializing the client.

<script src="https://cdn.pubnub.com/sdk/javascript/pubnub.10.0.0.js"></script>

Bundling

Use Rollup or Webpack to bundle only the modules you need.

Use our configuration file as a starting point.

Rollup
Webpack

Clone the PubNub JavaScript SDK repository to a directory of your choice.
In rollup.config.js, set enableTreeShaking to true.
Decide which modules to include. Disable the rest by setting environment variables, for example:
```
export PRESENCE_MODULE=disabled PUBLISH_MODULE=disabled
```
Run rollup -c rollup.config.js --bundleConfigAsCjs. The bundle is in the _your_js_sdk_repo_dir_/upload directory.

Clone the PubNub JavaScript SDK repository to a directory of your choice.

Create webpack.config.js based on the Rollup configuration file. Enable or disable modules with environment variables.

const webpack = require('webpack');

module.exports = {
  // Other configuration...
  plugins: [
    new webpack.DefinePlugin({
      'process.env.CRYPTO_MODULE': JSON.stringify(process.env.CRYPTO_MODULE ?? 'enabled'),
      'process.env.SHARED_WORKER': JSON.stringify(process.env.SHARED_WORKER ?? 'enabled'),
      'process.env.PUBLISH_MODULE': JSON.stringify(process.env.PUBLISH_MODULE ?? 'enabled'),
      'process.env.SUBSCRIBE_MODULE': JSON.stringify(process.env.SUBSCRIBE_MODULE ?? 'enabled'),
      'process.env.SUBSCRIBE_EVENT_ENGINE_MODULE': JSON.stringify(process.env.SUBSCRIBE_EVENT_ENGINE_MODULE ?? 'enabled'),
      'process.env.SUBSCRIBE_MANAGER_MODULE': JSON.stringify(process.env.SUBSCRIBE_MANAGER_MODULE ?? 'enabled'),
      'process.env.PRESENCE_MODULE': JSON.stringify(process.env.PRESENCE_MODULE ?? 'enabled'),
      'process.env.PAM_MODULE': JSON.stringify(process.env.PAM_MODULE ?? 'enabled'),
      'process.env.CHANNEL_GROUPS_MODULE': JSON.stringify(process.env.CHANNEL_GROUPS_MODULE ?? 'enabled'),
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Webpack configuration

Add any other necessary configuration to webpack.config.js. See Webpack documentation.

Disable unnecessary modules by setting environment variables, for example:
```
export PRESENCE_MODULE=disabled PUBLISH_MODULE=disabled
```
Run npx webpack --config webpack.config.js. Find the bundle in the output directory you configured.

Initialization

Initialize the PubNub Client API and set publish and subscribe keys. You can create an account and get your keys from the Admin Portal.

Method(s)

To Initialize PubNub, you can use the following method(s) in the JavaScript SDK:

pubnub.PubNub({
  subscribeKey: string,
  publishKey: string,
  userId: string,
  authKey: string,
  logVerbosity: boolean,
  ssl: boolean,
  origin: string | string[],
  presenceTimeout: number,
  heartbeatInterval: number,
  keepAlive: boolean,
  keepAliveSettings: any,
  suppressLeaveEvents: boolean,
  requestMessageCountThreshold: number,
  enableEventEngine: boolean
show all 25 lines

* required

Parameter	Description
`subscribeKey` * Type: string Default: n/a	Specifies the `subscribeKey` to be used for subscribing to a channel. This key can be specified at initialization or along with a `subscribe()`.
`publishKey` Type: string Default: n/a	Specifies the `publishKey` to be used for publishing messages to a channel. This key can be specified at initialization or along with a `publish()`.
`userId` * Type: string Default: n/a	`userId` to use. You should set a unique `userId` to identify the user or the device that connects to PubNub. It's a UTF-8 encoded string of up to 92 alphanumeric characters. If you don't set the `userId`, you won't be able to connect to PubNub.
`secretKey` Type: string Default: n/a	Secret key from Admin Portal. When you initialize PubNub with `secretKey`, you get root permissions for Access Manager. For more information, refer to Server Operations.
`authKey` Type: string Default: n/a	The token returned from Access Manager that provides access to resources. For more information, refer to Access Manager.
`logVerbosity` Type: boolean Default: `false`	Log HTTP information. For information on enabling logging and collecting logs for troubleshooting, see Logging.
`ssl` Type: boolean Default: `true` for v4.20.0 onwards, `false` before v4.20.0	If set to `true`, requests will be made over HTTPS.
`origin` Type: string or string[] Default: `ps.pndsn.com`	If a custom domain is required, SDK accepts it here. To request a custom domain, contact support and follow the request process.
`presenceTimeout` Type: number Default: `300`	How long the server considers the client alive for presence. The client sends periodic requests to stay active. If no heartbeat arrives within the timeout, the client is marked inactive and a "timeout" event is emitted on the presence channel.
`heartbeatInterval` Type: number Default: `Not Set`	How often the client sends heartbeats. To shorten presence timeout, set roughly to `(presenceTimeout / 2) - 1`. Minimum value is `3`.
`keepAlive` Type: boolean Default: `false`	If set to `true`, SDK will use the same TCP connection for each HTTP request, instead of opening a new one for each new request.
`keepAliveSettings` Type: any Default: `keepAliveMsecs`: 1000 `freeSocketKeepAliveTimeout`: 15000 `timeout`: 30000 `maxSockets`: Infinity `maxFreeSockets`: 256	Set a custom parameters for setting your connection `keepAlive` if this is set to `true`. `keepAliveMsecs: (Number)` how often to send TCP KeepAlive packets over sockets. `freeSocketKeepAliveTimeout: (Number)` sets the free socket to timeout after freeSocketKeepAliveTimeout milliseconds of inactivity on the free socket. `timeout: (Number)` sets the working socket to timeout after timeout milliseconds of inactivity on the working socket. `maxSockets: (Number)` maximum number of sockets to allow per host. `maxFreeSockets: (Number)` maximum number of sockets to leave open in a free state.
`suppressLeaveEvents` Type: boolean Default: `false`	When `true` the SDK doesn't send out the leave requests.
`requestMessageCountThreshold` Type: number Default: `100`	Emits `PNRequestMessageCountExceededCategory` when payload message count exceeds the threshold.
`enableEventEngine` Type: boolean Default: `false`	Whether to use the recommended standardized workflows for subscribe and presence, optimizing how the SDK internally handles these operations and which statuses it emits. Refer to SDK connection lifecycle for more information. This flag affects the following parameters: `autoNetworkDetection` is ignored when `enableEventEngine` is `true` `maintainPresenceState` is automatically enabled when `enableEventEngine` is `true`
`restore` Type: boolean Default: `false`	This option is available only in the browser environment and requires `listenToBrowserNetworkEvents` to be set to `true`. A flag to allow catch up on the front-end applications. Its main purpose is to manage the state in which the SDK will be set after the network goes down: `true` — moves the client into the `disconnected` state without sending any `leave` events. It keeps the current timetoken and the list of active channels and groups intact. This option also allows for the network restore to try to catch up on messages that were missed when the client was offline. `false` — the client will reset the current timetoken as well as the list of active channels and groups.
`retryConfiguration` Type: `RequestRetryPolicy` Default: `PubNub.ExponentialRetryPolicy` (subscribe only)	This option is available in the browser and Node.js environments. Custom reconnection configuration parameters. You can specify one or more endpoint groups for which the retry policy won't be applied. `retryConfiguration: policy` is the type of policy to be used. Available values: `PubNub.NoneRetryPolicy()` `PubNub.LinearRetryPolicy({ delay, maximumRetry, excluded })` `PubNub.ExponentialRetryPolicy({ minimumDelay, maximumDelay, maximumRetry, excluded })` `excluded` takes an array of `Endpoint` enum values, for example, `excluded: [PubNub.Endpoint.MessageSend]`. For more information, refer to SDK connection lifecycle.
`autoNetworkDetection` Type: boolean Default: `false`	This option is available in the browser and Node.js environments, only when `enableEventEngine` is `false`. Whether the SDK should emit the `PNNetworkDownCategory` and `PNNetworkUpCategory` statuses on network status change.
`listenToBrowserNetworkEvents` Type: boolean Default: `true`	This option is available only in the browser environment. Whether the SDK should emit the `PNNetworkDownCategory` and `PNNetworkUpCategory` statuses, listen for the browser reachability events, and try to reconnect on network status change. If the browser fails to detect the network changes from WiFi to LAN or you get reconnection issues, set the flag to `false`. This allows the SDK reconnection logic to take over.
`maintainPresenceState` Type: boolean Default: `true`	Works only when `enableEventEngine` is `true`. Whether the custom presence state information set using `pubnub.setState()` should be sent every time the SDK sends a subscribe call.
`cryptoModule` Type: `PubNub.CryptoModule.legacyCryptoModule({ cipherKey, useRandomIVs })` `PubNub.CryptoModule.aesCbcCryptoModule({cipherKey})` Default: None	The cryptography module used for encryption and decryption of messages and files. Takes the `cipherKey` and `useRandomIVs` parameters as arguments. For more information, refer to the cryptoModule section.
`subscriptionWorkerUrl` Type: string Default: None	The URL for the shared worker on the server or the origin as the page where it's used. For more information, refer to Shared workers.
~~`cipherKey`~~ Type: ~~string~~ Default: n/a	This way of setting this parameter is deprecated, pass it to `cryptoModule` instead. ~~If passed, will encrypt the payloads.~~
~~`useRandomIVs`~~ Type: ~~boolean~~ Default: ~~`true`~~	This way of setting this parameter is deprecated, pass it to `cryptoModule` instead. ~~When `true` the initialization vector (IV) is random for all requests (not just for file upload). When `false` the IV is hard-coded for all requests except for file upload.~~
~~`uuid`~~ * Type: ~~string~~ Default: n/a	This parameter is deprecated, use `userId` instead. `UUID` to use. You should set a unique `UUID` to identify the user or the device that connects to PubNub. If you don't set the `UUID`, you won't be able to connect to PubNub.

Disabling random initialization vector

Disable random initialization vector (IV) only for backward compatibility (<4.31.0) with existing applications. Never disable random IV on new applications.

`cryptoModule`

cryptoModule encrypts and decrypts messages and files. From 7.3.3 onward, you can configure the algorithms it uses.

Each SDK includes two options: legacy 128-bit encryption and recommended 256-bit AES-CBC. For background, see Message Encryption and File Encryption.

If you do not explicitly set the cryptoModule in your app and have the cipherKey and useRandomIVs params set in PubNub config, the client defaults to using the legacy encryption.

For detailed encryption configuration, utility methods for encrypting/decrypting messages and files, and practical examples, see the dedicated Encryption page.

Legacy encryption with 128-bit cipher key entropy

You don't have to change your encryption configuration if you want to keep using the legacy encryption. If you want to use the recommended 256-bit AES-CBC encryption, you must explicitly set that in PubNub config.

Shared workers

Shared workers manage concurrent connections and presence across multiple client instances (tabs or windows). Source code:

http://cdn.pubnub.com/sdk/javascript/pubnub.worker.10.0.0.js

Reasons to use shared workers:

Browsers limit the number of parallel connections to the same origin (e.g., ps.pndsn.com) which may produce connection issues. Shared workers aggregate subscriptions for matching keysets, allowing them to use one long-poll subscribe request.
When a long-poll subscribe request connection is closed, it can lead to false leave events if multiple tabs or windows are open. The shared worker tracks channels and groups to ensure long-poll requests are only terminated when all associated tabs or windows are closed.

Hosting a shared worker

As browsers enforce the Same-origin Policy, you must host the shared worker under the same origin as the client application. Pages loaded from different origins won't be able to share a worker.

Configuration

Download the shared worker source code from our CDN.

http://cdn.pubnub.com/sdk/javascript/pubnub.worker.10.0.0.js

Host the shared worker on your server or make it available under the same origin as the page where it's used according to the Same-origin Policy.
Configure the subscriptionWorkerUrl property when initializing the PubNub client:

When set, the client downloads the shared worker and uses it to manage subscriptions.

Worker version

The version of the shared worker must match the version of the PubNub client being used.

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.

Initialize with your subscribeKey, publishKey, and a userId that identifies the client.

Required User ID

Always set the userId to uniquely identify the user or device that connects to PubNub. This userId should be persisted and should remain unchanged for the lifetime of the user or the device. If you don't set the userId, you won't be able to connect to PubNub.

Server operations

Servers can run multiple instances on the same machine and don’t use end‑user authentication. Initialize with secretKey to administer Access Manager; this grants server‑side access to all channels and channel groups.

Secure your secretKey

Anyone with the secretKey can grant and revoke permissions to your app. Never let your secretKey be discovered, and only exchange and deliver it securely. Only use the secretKey on secure environments such as Node.js applications or other server-side platforms.

Required User ID

var pubnub = new PubNub({
    subscribeKey: "mySubscribeKey",
    publishKey: "myPublishKey",
    userId: "myUniqueUserId",
    secretKey: "secretKey",
    heartbeatInterval: 0
});

Now that the pubnub object is instantiated, the client will be able to access the Access Manager functions. The pubnub object will use the secretKey to sign all Access Manager messages to the PubNub Network.

Other examples

Initialization for a Read-Only client

In the case where a client will only read messages and never publish to a channel, you can simply omit the publishKey when initializing the client:

Required User ID

Initializing with SSL enabled

This examples demonstrates how to enable PubNub Transport Layer Encryption with TLS (formerly known as SSL). Just initialize the client with ssl set to true. The hard work is done, now the PubNub API takes care of the rest. Just subscribe and publish as usual and you are good to go.

Required User ID

Event listeners

PubNub SDKs provide several sources for real-time updates:

The PubNub client can receive updates from all subscriptions: all channels, channel groups, channel metadata, and users.
The Subscription object can receive updates only for the particular object for which it was created: channel, channel group, channel metadata, or user.
The SubscriptionsSet object can receive updates for all objects for which a list of subscription objects was created.

To work with these sources, the SDK provides local representations of server entities, so you can subscribe and add handlers per entity. For details, see Publish & Subscribe.

User ID

A userId (Universal Unique Identifier) is a required unique alphanumeric identifier used to identify the client to the PubNub platform. Each client must pass a userId that represents the user or the device that connects to PubNub.

Set user ID

Set the userId parameter when you instantiate a PubNub instance (new PubNub()). It's important that your application reuse the userId on each device instead of generating a new userId on each connection.

Required User ID

var pubnub = new PubNub({
    subscribeKey: "mySubscribeKey",
    publishKey: "myPublishKey",
    userId: "myUniqueUserId"
});

You can also call the following method to explicitly set the userId:

pubnub.setUserId(string)

* required

Parameter	Description
`userId` * Type: String	`userId` to set.

pubnub.setUserId("myUniqueUserId")

Save user ID

Providing a value for the userId parameter in the PubNub object initialization will result in that value getting saved in the browser's localStorage key (described above) automatically by the PubNub SDK. You may implement a different local caching strategy, as required.

Consider the following when implementing a userId reuse strategy:

On your server, generate a userId when a user creates a user profile (user registration process). You can generate this with the SDK, or by another method of your choosing.
Pass the userId back to the user upon successful login (authentication process).
Persist the userId on the device where it can be retrieved the next time the PubNub instance is instantiated. The PubNub instance might be instantiated multiple times as the app is left and re-entered, and you may not require a login with each new session.

Get user ID

Use this method to get the current userId set on your application. This method doesn't take any arguments.

pubnub.getUserId();

Required User ID recommendation

Remember that whatever user ID you use is visible to other users (if a user peeks behind the scenes using the browser console or other tools), so you should not use a username or email as the userId. The userId should be something that can be easily replaced as required without user interaction or even knowledge that it has happened.

Authentication key

This function provides the capability to reset a user's auth Key.

Typically auth Key is specified during initialization for Access Manager enabled applications. In the event that auth Key has expired or a new auth Key is issued to the client from a Security Authority, the new auth Key can be sent using setAuthKey().

Property

To Set Authentication Key you can use the following method(s) in the JavaScript SDK

pubnub.setAuthKey(string)

* required

Parameter	Description
`key` * Type: String	`Auth key` to set.

Sample code

Returns

None.

Filter expression

Requires Stream Controller add-on

This method requires that the Stream Controller add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.

Stream filtering allows a subscriber to apply a filter to only receive messages that satisfy the conditions of the filter. The message filter is set by the subscribing client(s) but it is applied on the server side thus preventing unwanted messages (those that do not meet the conditions of the filter) from reaching the subscriber.

To set or get message filters, you can use the following method. To learn more about filtering, refer to the Publish Messages documentation.

Method(s)

pubnub.setFilterExpression(
  filterExpression: string
)

* required

Parameter	Description
`filterExpression` * Type: string	PSV2 feature to `subscribe` with a custom filter expression.

pubnub.getFilterExpression()

This method doesn't take any arguments.

Configuration API for JavaScript SDK

Bundling

Webpack configuration

Initialization

Method(s)

Disabling random initialization vector

`cryptoModule`

Legacy encryption with 128-bit cipher key entropy

Shared workers

Hosting a shared worker

Configuration

Worker version

Sample code

Reference code

Required User ID

Server operations

Secure your secretKey

Required User ID

Other examples

Initialization for a Read-Only client

Required User ID

Initializing with SSL enabled

Required User ID

Event listeners

User ID

Set user ID

Required User ID

Save user ID

Get user ID

Required User ID recommendation

Authentication key

Property

Sample code

Returns

Filter expression

Requires Stream Controller add-on

Method(s)

Sample code

Set filter expression

Get filter expression

Bundling​

Webpack configuration

Initialization​

Method(s)​

Disabling random initialization vector

cryptoModule​

Legacy encryption with 128-bit cipher key entropy

Shared workers​

Hosting a shared worker

Configuration​

Worker version

Sample code​

Reference code

Required User ID

Server operations​

Secure your secretKey

Required User ID

Other examples​

Initialization for a Read-Only client​

Required User ID

Initializing with SSL enabled​

Required User ID

Event listeners​

User ID​

Set user ID​

Required User ID

Save user ID​

Get user ID​

Required User ID recommendation

Authentication key​

Property​

Sample code​

Returns​

Filter expression​

Requires Stream Controller add-on

Method(s)​

Sample code​

Set filter expression​

Get filter expression​

Bundling

Initialization

Method(s)

`cryptoModule`

Shared workers

Configuration

Sample code

Server operations

Other examples

Initialization for a Read-Only client

Initializing with SSL enabled

Event listeners

User ID

Set user ID

Save user ID

Get user ID

Authentication key

Property

Sample code

Returns

Filter expression

Method(s)

Sample code

Set filter expression

Get filter expression