Systems Architecture for Agentic AI in Next.js

Description and use

An event‑driven architecture decouples agent execution from presentation, reducing UI latency and enabling horizontal scaling in Next.js applications.

Problem

Agentic applications built on monolithic request-response patterns suffer from slow, brittle behavior due to multi-step reasoning loops, API gateway timeouts, and frontend sluggishness.

Outcome

The platform achieved sub‑50 ms perceived UI latency, eliminated serverless runtime limits, and scaled horizontally to handle thousands of concurrent multi‑step reasoning sessions.

Workflow

• 1. User submits a task via Next.js frontend. 2. Serverless function queues the task in a message broker and returns 202 Accepted. 3. Background workers process each agent step (plan, act, reflect) and emit AgentStep objects. 4. WebSocket channel streams AgentStep updates to the browser. 5. Frontend renders optimistic UI updates, showing the agent’s thought process in real time.

Evidence

We introduced a message broker. This allows us to queue agent tasks immediately. Once a task is submitted, the serverless function can return a 202 Accepted status, freeing up resources while the heavy lifting happens in the background.

Source

Our perceived UI latency dropped to sub‑50ms because the frontend no longer waited for the entire agent workflow to finish before showing the first "thought."

Source