The AI Cloud Layer

15. The AI Cloud Layer

This is Vercel's biggest strategic bet and growth area. As an SE in 2026, you need to understand and demo this layer.

15.1 Vercel AI SDK

Open-source SDK for building AI-powered applications. The industry standard for AI in Next.js.

// Streaming chat with any LLM provider
import { streamText } from 'ai';
import { openai } from '@ai-sdk/openai';
import { anthropic } from '@ai-sdk/anthropic';

export async function POST(request) {
  const { messages } = await request.json();
  
  const result = streamText({
    model: openai('gpt-4o'),   // or anthropic('claude-3-5-sonnet')
    messages,
    system: 'You are a helpful assistant.',
  });
  
  return result.toDataStreamResponse();  // streams to browser
}

Client-side:

'use client';
import { useChat } from 'ai/react';

export function Chat() {
  const { messages, input, handleSubmit, handleInputChange } = useChat();
  
  return (
    <div>
      {messages.map(m => <div key={m.id}>{m.content}</div>)}
      <form onSubmit={handleSubmit}>
        <input value={input} onChange={handleInputChange} />
        <button type="submit">Send</button>
      </form>
    </div>
  );
}

15.2 AI SDK 6 — Agent abstraction layer (October 2025)

AI SDK 6 added:

• Agent definition layer — define reusable agents once, use across the app
• Tool execution approval — human-in-the-loop for sensitive operations
• Type safety across models — compile-time checks for model/UI data
• Durable workflow tooling — long-running agents that survive function timeouts

15.3 use-workflow (durable workflows)

Solves the function timeout problem for long-running AI agents:

import { workflow } from 'use-workflow';

export const researchAgent = workflow(async (ctx, topic: string) => {
  // Each step is durable — if the function times out, execution resumes
  const sources = await ctx.run('search', () => searchWeb(topic));
  const summary = await ctx.run('summarize', () => llm.summarize(sources));
  const report = await ctx.run('format', () => formatReport(summary));
  return report;
});

15.4 Vercel AI Gateway

Unified interface to 100+ AI models from a single endpoint. Handles:

• Model routing and fallback
• Rate limiting per model/provider
• Cost tracking and observability
• No code changes to switch providers

15.5 Vercel Sandbox

Isolated compute environments for agents that need to execute code:

// Agent executes code in an isolated sandbox — no security risk
const sandbox = await createSandbox();
const result = await sandbox.execute(`
  import pandas as pd
  df = pd.read_csv('data.csv')
  print(df.describe())
`);

15.6 v0 — AI App Builder

• Converts natural language prompts to production-ready React/Next.js code
• 4M+ users by early 2026
• Deployed directly to Vercel with one click
• Backed by Vercel's own frontend-optimised AI model (released May 2025)

15.7 Fluid Compute + AI = cost efficiency

For AI workloads specifically:

• LLM call = mostly I/O wait (waiting for the model)
• Traditional serverless: you pay for all the wait time
• Fluid Compute: you pay only for the ~10ms of actual code execution around the LLM call
• Result: 80-90% cost reduction for AI streaming routes