Stream Chat

Stream Chat is a scalable in-app chat platform providing the infrastructure for real-time messaging without teams managing WebSocket servers, message storage, or delivery guarantees. Its REST API covers channel creation and management, message sending and retrieval, reactions, threads, file attachments, and moderation. For agents building or managing chat features, Stream's server-side API enables programmatic message sending, channel lifecycle management, and moderation operations on behalf of or alongside users.

The API surface is comprehensive for chat use cases — channels, messages, members, reactions, threads, moderation, webhooks, and push notification triggers. The server-side API enables agents to create channels for new user pairs or groups, send system messages, moderate content by flagging or removing messages, and query message history. The webhook system delivers real-time events for new messages, channel updates, and moderation actions.

Authentication uses API keys and server-side secrets for backend management operations. User tokens are generated server-side by signing with the API secret — agents control token generation and expiry. The key/secret model is well-suited for server-side agent integration that needs to impersonate or manage users without exposing credentials client-side.

Reliability is production-grade with Stream's infrastructure handling WebSocket connection management, message persistence, and delivery guarantees. Stream publishes uptime history and maintains the availability infrastructure required for real-time chat features. Teams relying on Stream for primary user communication should implement webhook-based failure monitoring.

Documentation is excellent and comprehensive. The server-side API reference covers all management operations with clear request/response examples. The moderation API documentation is thorough for teams implementing content moderation workflows. Stream's documentation is a notable strength — among the better API documentation sets in the chat infrastructure space.