How to use Anthropic Claude API — a practical guide

If you're here, you probably want working code in five minutes. That's exactly what this guide does.

1. 1
   Register at console.anthropic.com.
2. 2
   Create a key (sk-ant-…).
3. 3
   Install the SDK: `npm install @anthropic-ai/sdk`.
4. 4
   Call messages.create with model, max_tokens, messages.

import Anthropic from "@anthropic-ai/sdk";

const client = new Anthropic();

const msg = await client.messages.create({
  model: "claude-sonnet-4-20250514",
  max_tokens: 1024,
  messages: [
    { role: "user", content: "סכם את המאמר הזה בפסקה אחת: ..." },
  ],
});

console.log(msg.content[0].text);