AG-UI Protocol

AG-UI is the open, lightweight Agent-User Interaction Protocol, streaming structured JSON events over standard HTTP to achieve real-time synchronization between any AI agent backend and its frontend interface.

This is the Agent-User Interaction Protocol (AG-UI), an open standard launched by CopilotKit in 2025. It defines a structured, event-driven stream using JSON over standard HTTP, eliminating the need for custom WebSocket formats and text parsing hacks. AG-UI ensures perfect, real-time synchronization of critical data: messages, tool calls, and state patches flow seamlessly between your agent backend and the UI. Developers can integrate quickly using the TypeScript or Python SDK, establishing a consistent contract for building dynamic, human-in-the-loop AI applications with zero vendor lock-in.

https://ag-ui.com