Grok 4.3 Is Now Available in Puter.js

Puter.js now supports Grok 4.3, xAI's latest flagship reasoning model with major gains in agentic performance and a roughly 20% lower cost than its predecessor Grok 4.20.

What is Grok 4.3?

Grok 4.3 is xAI's newest frontier model, designed for agentic workflows, instruction following, and tasks demanding high factual accuracy. It accepts text and image inputs with always-on reasoning that cannot be disabled, and supports a 1M token context window with no output token limit—making it well suited for long-document analysis and multi-step agent pipelines.

Key highlights:

• +321 Elo on GDPval-AA — a major jump in real-world agentic task performance versus Grok 4.20, surpassing most competitors on the benchmark
• 98% on τ²-Bench Telecom — gains 5 points over Grok 4.20, demonstrating top-tier tool-use reliability
• 81% on IFBench — frontier-class instruction-following accuracy
• 1M Token Context, Unlimited Output — process entire codebases or long documents and generate responses of any length
• 20% Cheaper to Run — at $1.25 per million input tokens and $2.50 per million output tokens, it scores higher on the Artificial Analysis Intelligence Index while costing less than Grok 4.20

Examples

Text generation

puter.ai.chat("Explain how reinforcement learning from human feedback works",
  { model: 'x-ai/grok-4.3' }
);

Streaming

const response = await puter.ai.chat(
  "Write a step-by-step plan to migrate a monolithic Rails app to microservices",
  { model: 'x-ai/grok-4.3', stream: true }
);

for await (const part of response) {
  puter.print(part?.text);
}

Tool calling

function getStockPrice(ticker) {
    const mockPrices = {
        'AAPL': '$210.45',
        'TSLA': '$285.12',
        'NVDA': '$540.88',
    };
    return mockPrices[ticker] || 'Unknown';
}

const tools = [{
    type: "function",
    function: {
        name: "get_stock_price",
        description: "Get the current stock price for a ticker symbol",
        parameters: {

function getStockPrice(ticker) {
    const mockPrices = {
        'AAPL': '$210.45',
        'TSLA': '$285.12',
        'NVDA': '$540.88',
    };
    return mockPrices[ticker] || 'Unknown';
}

const tools = [{
    type: "function",
    function: {
        name: "get_stock_price",
        description: "Get the current stock price for a ticker symbol",
        parameters: {
            type: "object",
            properties: {
                ticker: {
                    type: "string",
                    description: "Stock ticker symbol e.g. AAPL, TSLA"
                }
            },
            required: ["ticker"]
        }
    }
}];

const userInput = "What's the current price of NVDA?";
const completion = await puter.ai.chat(userInput, {
    model: 'x-ai/grok-4.3',
    tools,
});

if (completion.message.tool_calls?.length > 0) {
    const toolCall = completion.message.tool_calls[0];
    const args = JSON.parse(toolCall.function.arguments);
    const price = getStockPrice(args.ticker);

    const finalResponse = await puter.ai.chat([
        { role: "user", content: userInput },
        completion.message,
        {
            role: "tool",
            tool_call_id: toolCall.id,
            content: price
        }
    ], { model: 'x-ai/grok-4.3' });

    console.log(finalResponse);
}

Image analysis

puter.ai.chat(
    "Describe what is happening in this image",
    "https://assets.puter.site/doge.jpeg",
    { model: 'x-ai/grok-4.3' }
);

Long-context document analysis

puter.ai.chat(`Review the following technical specification end-to-end and produce
a checklist of ambiguous requirements, missing edge cases, and potential failure modes:
${longSpec}`,
  { model: 'x-ai/grok-4.3' }
);

Get Started Now

Just add one library to your project:

// npm install @heyputer/puter.js
import { puter } from '@heyputer/puter.js';

Or add one script tag to your HTML:

<script src="https://js.puter.com/v2/"></script>

No API keys and no infrastructure setup. Start building with Grok 4.3 immediately.

Learn more:

• Free, Unlimited Grok API
• Puter.js AI Documentation