Claude Opus 4.1 API

Access Claude Opus 4.1 from Anthropic using Puter.js AI API.

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Model Card

Claude Opus 4.1 is an August 2025 incremental upgrade to Opus 4 focused on agentic tasks and real-world coding. It improved coding accuracy to 74.5% on SWE-bench with finer-grained refactoring and more precise bug fixes.

Context Window 200K

tokens

Max Output 32K

tokens

Input Cost $15

per million tokens

Output Cost $75

per million tokens

Input text, image, pdf

modalities

Tool Use Yes

 

Knowledge Cutoff Mar 31, 2025

 

Release Date Aug 5, 2025

 

API Usage Example

Add Claude Opus 4.1 to your app with just a few lines of code.
No API keys, no backend, no configuration required.

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

puter.ai.chat("Explain quantum computing in simple terms", {
    model: "anthropic/claude-opus-4-1"
}).then(response => {
    document.body.innerHTML = response.message.content;
});

<html>
<body>
    <script src="https://js.puter.com/v2/"></script>
    <script>
        puter.ai.chat("Explain quantum computing in simple terms", {
            model: "anthropic/claude-opus-4-1"
        }).then(response => {
            document.body.innerHTML = response.message.content;
        });
    </script>
</body>
</html>

View full documentation →

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Frequently Asked Questions

What is this Claude Opus 4.1 API about?

The Claude Opus 4.1 API gives you access to Anthropic's chat model through Puter.js. With just a few lines of JavaScript, you can integrate Claude Opus 4.1 into any web app or Node.js project — no API keys, no backend, and no configuration required.

Who created Claude Opus 4.1?

Claude Opus 4.1 was created by Anthropic and released on Aug 5, 2025.

What is the context window of Claude Opus 4.1?

Claude Opus 4.1 supports a context window of 200K tokens. For reference, that is roughly equivalent to 400 pages of text.

What is the max output length of Claude Opus 4.1?

Claude Opus 4.1 can generate up to 32K tokens in a single response.

What is the knowledge cutoff of Claude Opus 4.1?

Claude Opus 4.1 has a knowledge cutoff date of Mar 31, 2025. This means the model was trained on data available up to that date.

What types of input can Claude Opus 4.1 process?

Claude Opus 4.1 accepts the following input types: text, image, pdf. It produces: text.

Does Claude Opus 4.1 support tool use (function calling)?

Yes, Claude Opus 4.1 supports tool use (function calling), allowing it to interact with external tools, APIs, and data sources as part of its response flow.

How much does it cost?
The Claude Opus 4.1 API is available through the User-Pays Model. As a developer, you can add the Claude Opus 4.1 API to your app for free — your users pay for their own AI costs directly.
Price per 1M tokens
Input$15
Output$75
How do I access the Claude Opus 4.1 API?

You can access the Claude Opus 4.1 API with just a few lines of JavaScript — no API keys, no backend, and no configuration required. Include the Puter.js library in your project and start making calls right away. For more details, check out our documentation.

Does the Claude Opus 4.1 API work with React / Vue / Vanilla JS / Node / etc.?

Yes — the Claude Opus 4.1 API works with any JavaScript framework, Node.js, or plain HTML through Puter.js. Just include the library and start building. See the documentation for more details.

Get started with Puter.js

Add Claude Opus 4.1 to your app without worrying about API keys or setup.

Read the Docs View Tutorials