Real Time Bidirectional Websocket Message Streaming With Step Tracking

via “real-time event streaming with websocket and server-sent events”

The Frontend Stack for Agents & Generative UI. React + Angular. Makers of the AG-UI Protocol

Unique: Implements dual-mode streaming (WebSocket primary, SSE fallback) with automatic reconnection and event filtering. Handles connection lifecycle transparently, abstracting framework-specific WebSocket APIs (Express.js ws, Next.js WebSocket, Hono WebSocket, FastAPI WebSocket).

vs others: More robust than simple HTTP polling; CopilotKit's WebSocket implementation includes automatic reconnection, event buffering, and framework-agnostic abstraction. SSE fallback provides compatibility with restrictive hosting environments (Vercel, Netlify) where WebSocket may be limited.