Azure Web PubSub service client library for Java

Use the library to:

  • Send messages to hubs and groups.
  • Send messages to particular users and connections.
  • Organize users and connections into groups.
  • Close connections
  • Grant/revoke/check permissions for an existing connection
Source code API Reference Documentation Product Documentation Samples

Getting started


Include the Package


Create a Web PubSub client using connection string

WebPubSubServiceClient webPubSubServiceClient = new WebPubSubClientBuilder()

Create a Web PubSub client using access key

WebPubSubServiceClient webPubSubServiceClient = new WebPubSubClientBuilder()
    .credential(new AzureKeyCredential("{access-key}"))
    .endpoint("<Insert endpoint from Azure Portal>")

Create a Web PubSub Group client

WebPubSubServiceClient webPubSubServiceClient = new WebPubSubClientBuilder()
    .credential(new AzureKeyCredential("{access-key}"))
WebPubSubGroup javaGroup = webPubSubServiceClient.getGroup("java");

Key concepts


Connections, represented by a connection id, represent an individual websocket connection to the Web PubSub service. Connection id is always unique.


Hub is a logical concept for a set of connections. Connections are always connected to a specific hub. Messages that are broadcast to the hub are dispatched to all connections to that hub. Hub can be used for different applications, different applications can share one Azure Web PubSub service by using different hub names.


Group allow broadcast messages to a subset of connections to the hub. You can add and remove users and connections as needed. A client can join multiple groups, and a group can contain multiple clients.


Connections to Web PubSub can belong to one user. A user might have multiple connections, for example when a single user is connected across multiple devices or multiple browser tabs.


Using this library, you can send messages to the client connections. A message can either be string text, JSON or binary payload.


Broadcast message to entire hub

webPubSubServiceClient.sendToAll("Hello world!");

Broadcast message to a group

WebPubSubGroup javaGroup = webPubSubServiceClient.getGroup("Java");
javaGroup.sendToAll("Hello Java!");

Send message to a connection

webPubSubServiceClient.sendToConnection("myconnectionid", "Hello connection!");

Send message to a user

webPubSubServiceClient.sendToUser("Andy", "Hello Andy!");


Enable client logging

You can set the AZURE_LOG_LEVEL environment variable to view logging statements made in the client library. For example, setting AZURE_LOG_LEVEL=2 would show all informational, warning, and error log messages. The log levels can be found here: log levels.

Default HTTP Client

All client libraries by default use the Netty HTTP client. Adding the above dependency will automatically configure the client library to use the Netty HTTP client. Configuring or changing the HTTP client is detailed in the HTTP clients wiki.

Default SSL library

All client libraries, by default, use the Tomcat-native Boring SSL library to enable native-level performance for SSL operations. The Boring SSL library is an uber jar containing native libraries for Linux / macOS / Windows, and provides better performance compared to the default SSL implementation within the JDK. For more information, including how to reduce the dependency size, refer to the performance tuning section of the wiki.

Next steps

  • Samples are explained in detail here.

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