Prerequisites

You need a Google account and a free Google AI Studio API key. Sign up at aistudio.google.com.

Install the SDK

```

npm install @google/generative-ai

```

Your First Request

```javascript

import { GoogleGenerativeAI } from "@google/generative-ai";

const genAI = new GoogleGenerativeAI(process.env.GEMINI_API_KEY);

const model = genAI.getGenerativeModel({ model: "gemini-2.5-flash" });

const result = await model.generateContent("Explain quantum entanglement simply");

console.log(result.response.text());

```

Model Selection Guide

**gemini-2.5-flash** — Best for most use cases: fast, cheap, capable. Use this first.

**gemini-2.5-pro** — Complex reasoning, long documents, difficult coding tasks. Costs more.

**gemini-2.5-flash-lite** — Ultra-fast, ultra-cheap. Ideal for classification, summarization, batch jobs.

Free Tier Limits

Google AI Studio free tier: 15 RPM, 1 million tokens/day. No credit card required.