Build Real-Time Chat with Azure Communication Services

This skill builds real-time chat applications with the Azure Communication Chat SDK for Java (com.azure:azure-communication-chat, version 1.6.0), covering thread management, messaging, participants, and read receipts. A ChatClient (or async ChatAsyncClient) is built from an endpoint and a CommunicationTokenCredential wrapping a user access token - distinct classes handle distinct responsibilities: ChatClient creates/deletes chat threads and vends ChatThreadClients, while ChatThreadClient handles everything within a single thread (messages, participants, receipts). Creating a thread takes a topic and a list of ChatParticipants (each a CommunicationUserIdentifier plus display name), returning a thread ID used to get a ChatThreadClient for further operations. Messaging supports both TEXT and HTML content types via sendMessage, listing all messages (listMessages, paginated with a configurable maxPageSize, showing edited/deleted timestamps when applicable), fetching a single message, updating a message's content, and deleting a message. Participant management covers listing current participants, adding new ones with an optional shareHistoryTime to control how much prior message history a newly added participant can see, and removing a participant by identifier. Read receipts are sent per message (sendReadReceipt) and listed per thread (listReadReceipts, showing who read what and when), and typing notifications can be sent to signal active composition. Thread-level operations cover getting thread properties (topic, creation time), updating the topic, deleting the thread entirely, and listing all threads for the current user (with topic and last-message timestamp). Errors surface as HttpResponseException with specific handling suggested for 401 (check token), 403 (user not in thread), and 404 (thread not found). System message types (TOPIC_UPDATED, PARTICIPANT_ADDED, PARTICIPANT_REMOVED) are distinguished from TEXT/HTML user messages so they can be filtered out of a normal message view.

Use this skill when building real-time chat functionality in a Java application - group or one-to-one messaging, presence/typing indicators, read receipts, or thread-based conversations - on Azure Communication Services. It is not for building the token issuance/refresh service itself in depth (though the skill flags that user tokens expire and refresh logic via CommunicationTokenRefreshOptions is needed), and read receipts should only be sent when a message is genuinely viewed by the user, not automatically on receipt.

Input is thread topics, participant identifiers and display names, message content (text or HTML), and message/participant IDs for targeted operations. Output is created threads and messages with IDs and timestamps, paginated message/participant/receipt listings, and read-receipt and typing-notification confirmations.

Built on the Azure Communication Chat Java SDK (ChatClient, ChatThreadClient), authenticated via CommunicationTokenCredential backed by a user access token issued through Azure Communication Services.

<dependency>
    <groupId>com.azure</groupId>
    <artifactId>azure-communication-chat</artifactId>
    <version>1.6.0</version>
</dependency>

Java developers building real-time chat features - threaded messaging, participant management, read receipts, typing indicators - on Azure Communication Services rather than a custom WebSocket-based chat backend.