Claude Sonnet 4.5 API

Access Claude Sonnet 4.5 from Anthropic using Puter.js AI API.

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Model Card

Claude Sonnet 4.5 is Anthropic's most capable model for agents and computer use, released September 2025. It can maintain focus for 30+ hours on complex tasks, supports a 1M token context window (beta), and is described as their "most aligned frontier model."

Context Window

200K

tokens

Max Output

64,000

tokens

Input Cost

$3

per million tokens

Output Cost

$15

per million tokens

API Usage Example

Add Claude Sonnet 4.5 to your app with just a few lines of code.
No API keys, no backend, no configuration required.

<html>
<body>
    <script src="https://js.puter.com/v2/"></script>
    <script>
        puter.ai.chat("Explain quantum computing in simple terms", {
            model: "anthropic/claude-sonnet-4-5"
        }).then(response => {
            document.body.innerHTML = response.message.content;
        });
    </script>
</body>
</html>

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Get started with Puter.js

Add Claude Sonnet 4.5 to your app without worrying about API keys or setup.

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