The Vercel AI Frontend Stack

Vercel provides a complete stack for building AI-powered applications. Here's how the pieces fit together.

The Stack

AI Gateway

AI Gateway is your single point of access to AI models.

What It Does

Unified API - One API key for OpenAI, Anthropic, Google, and more
Caching - Reduce costs by caching identical requests
Rate limiting - Protect your application from abuse
Observability - Monitor usage, latency, and costs
Fallbacks - Automatically retry with backup models

Setup

Add AI_GATEWAY_API_KEY to your environment:

.env.local

AI_GATEWAY_API_KEY=your_api_key_here

Then use it with the AI SDK by specifying a model string e.g. anthropic/claude-sonnet-4.5.

AI SDK

The AI SDK provides the foundation for AI interactions.

Core Features

Streaming - Stream responses from any model
Tool calling - Let models call functions
Structured output - Get typed responses
Multi-modal - Handle text, images, and files

React Hooks

example.tsx

"use client";

import { useChat } from "@ai-sdk/react";

function Chat() {
  const [text, setText] = useState("");
  const { messages, sendMessage, status } = useChat({
    transport: new DefaultChatTransport({
      api: "/api/chat",
    }),
  });

  const handleSubmit = (e: React.FormEvent) => {
    e.preventDefault();
    sendMessage({ text: text });
    setText("");
  };

  return (
    <form onSubmit={handleSubmit}>
      {messages.map((m) => (
        <div key={m.id}>{m.content}</div>
      ))}
      <input value={text} onChange={(e) => setText(e.target.value)} />
    </form>
  );
}

Server Integration

app/api/chat/route.ts

import { streamText } from "ai";

export async function POST(req: Request) {
  const { messages } = await req.json();

  const result = streamText({
    model: "anthropic/claude-sonnet-4.5",
    system: "You are a helpful assistant.",
    messages: await convertToModelMessages(messages),
  });

  return result.toUIMessageStreamResponse();
}

AI Elements

AI Elements provides the UI layer on top of the AI SDK.

What It Adds

Pre-built components - Message, Conversation, PromptInput, and more
Streaming support - Components handle partial content gracefully
Composable design - Build exactly the UI you need
Theme integration - Works with your existing shadcn/ui setup

Integration Example

app/chat/page.tsx

"use client";

import { useChat } from "@ai-sdk/react";
import {
  Conversation,
  ConversationContent,
} from "@/components/ai-elements/conversation";
import {
  Message,
  MessageContent,
  MessageResponse,
} from "@/components/ai-elements/message";
import {
  PromptInput,
  PromptInputBody,
  PromptInputFooter,
  PromptInputProvider,
  PromptInputSubmit,
  PromptInputTextarea,
} from "@/components/ai-elements/prompt-input";

export default function ChatPage() {
  const { messages, sendMessage, status } = useChat({
    transport: new DefaultChatTransport({
      api: "/api/chat",
    }),
  });

  const handleSubmit = (message: { text: string }) => {
    sendMessage({ text: message.text });
  };

  return (
    <div className="h-screen flex flex-col">
      <Conversation className="flex-1">
        <ConversationContent>
          {messages.map((message) => (
            <Message key={message.id} from={message.role}>
              <MessageContent>
                {message.parts.map((part, i) =>
                  part.type === "text" ? (
                    <MessageResponse key={i}>{part.text}</MessageResponse>
                  ) : null,
                )}
              </MessageContent>
            </Message>
          ))}
        </ConversationContent>
      </Conversation>

      <PromptInputProvider>
        <PromptInput onSubmit={handleSubmit} className="p-4">
          <PromptInputBody>
            <PromptInputTextarea placeholder="Type a message..." />
          </PromptInputBody>
          <PromptInputFooter>
            <PromptInputSubmit status={status} />
          </PromptInputFooter>
        </PromptInput>
      </PromptInputProvider>
    </div>
  );
}

Putting It Together

The full flow:

User types in an AI Elements PromptInput
React hook (useChat) sends the message to your API route
AI SDK streams the response from the model via AI Gateway
AI Elements renders the streaming response in MessageResponse

Each layer handles its responsibility:

Layer	Responsibility
AI Gateway	Model access, caching, observability
AI SDK	Streaming, hooks, server integration
AI Elements	UI components, theming, accessibility

This separation means you can swap any layer independently. Use a different model provider, build custom hooks, or create your own components—the stack remains flexible.

The Vercel AI Frontend Stack

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