Vercel AI SDK Has a Free API — Here's How to Build AI Chat Apps in 20 Lines of Code

#ai #vercel #typescript #javascript

Why Vercel AI SDK?

The Vercel AI SDK gives you unified API for building AI apps. One SDK, every LLM provider: OpenAI, Anthropic, Google, Mistral, and more. Plus streaming, tool calling, and structured output built-in.

Free and open source. Works with any framework.

Getting Started

npm install ai @ai-sdk/openai

Simple Chat

import { generateText } from "ai";
import { openai } from "@ai-sdk/openai";

const { text } = await generateText({
  model: openai("gpt-4o"),
  prompt: "Explain Docker in 3 sentences."
});
console.log(text);

Streaming Chat

import { streamText } from "ai";
import { anthropic } from "@ai-sdk/anthropic";

const result = streamText({
  model: anthropic("claude-sonnet-4-20250514"),
  messages: [
    { role: "user", content: "Write a haiku about coding" }
  ]
});

for await (const chunk of result.textStream) {
  process.stdout.write(chunk);
}

Tool Calling

import { generateText, tool } from "ai";
import { z } from "zod";

const { text, toolResults } = await generateText({
  model: openai("gpt-4o"),
  tools: {
    weather: tool({
      description: "Get weather for a city",
      parameters: z.object({ city: z.string() }),
      execute: async ({ city }) => ({ temp: 22, condition: "sunny" })
    })
  },
  prompt: "Whats the weather in Tokyo?"
});

Structured Output

import { generateObject } from "ai";
import { z } from "zod";

const { object } = await generateObject({
  model: openai("gpt-4o"),
  schema: z.object({
    name: z.string(),
    pros: z.array(z.string()),
    cons: z.array(z.string()),
    rating: z.number().min(1).max(10)
  }),
  prompt: "Review TypeScript as a programming language"
});

console.log(object);

Next.js Route Handler

// app/api/chat/route.ts
import { streamText } from "ai";
import { openai } from "@ai-sdk/openai";

export async function POST(req: Request) {
  const { messages } = await req.json();
  const result = streamText({ model: openai("gpt-4o"), messages });
  return result.toDataStreamResponse();
}

Supported Providers

Provider	Package
OpenAI	@ai-sdk/openai
Anthropic	@ai-sdk/anthropic
Google	@ai-sdk/google
Mistral	@ai-sdk/mistral
Cohere	@ai-sdk/cohere
AWS Bedrock	@ai-sdk/amazon-bedrock

Need data for your AI app? Check out my Apify actors or email spinov001@gmail.com.

What AI SDK do you use? Share below!

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