Server-Sent Events Stream

InterfaceExperienceExperience & Human Oversightarc:ServerSentEventsStream

A unidirectional server-to-client streaming interface over a standard long-lived HTTP response carrying event-stream formatted token chunks.

Responsibility. Streams response events one way from agent to client over plain HTTP.

Also known as: SSE endpoint, Event-stream endpoint, /stream endpoint

Variant of Streaming Transport abstract

When to choose. Choose for most agent streaming workflows: the user submits a query, the agent streams a response, and no mid-stream client-to-server interaction is needed.

Direct neighbourhood (hover for relationship types)

Relationships

is routed to by dynamic

Layer-7 Load Balancer Ch2.9

alternative to variability

WebSocket Channel Ch2.9

Design guidance

SHOULD be the default streaming transport; reserve bidirectional channels for genuinely interactive scenarios.
MAY rely on standard HTTP middleware for authentication, rate limiting, and logging, and on standard load balancers without special configuration.

Classification

Technologies: Server-Sent EventsEventSource APIFastAPI StreamingResponseLangServe /streamLangServe /stream_log
Quality attributes: Maintainability (ISO/IEC 25010)Compatibility (ISO/IEC 25010)Performance efficiency (ISO/IEC 25010)

Sources

Ch2.9: T. Nguyen, "Streaming and Real-Time Responses," in Mastering Agentic AI Systems: Guide for the NVIDIA NCP-AAI Exam, 1st ed. 2026, ch. 2.9. ISBN: 9798244538229.