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Anthropic

Anthropic: Claude Opus 4.8 Fast

anthropic/claude-opus-4.8-fast

Try Claude Opus 4.8 Fast for free in your browser, and add it to your app for free with Puter.js AI API.

Try it free Add to your app
// npm install @heyputer/puter.js
import { puter } from '@heyputer/puter.js';

puter.ai.chat("Explain quantum computing in simple terms", {
    model: "anthropic/claude-opus-4.8-fast"
}).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-4.8-fast"
        }).then(response => {
            document.body.innerHTML = response.message.content;
        });
    </script>
</body>
</html>

Model Card

Claude Opus 4.8 Fast is a high-speed configuration of Anthropic's latest flagship model, delivering up to 2.5x faster output token generation at significantly lower cost than previous fast variants.

It runs the same Opus 4.8 model — which improves on Opus 4.7 in agentic coding (69.2% vs 64.3%), multidisciplinary reasoning with tools (57.9% vs 54.7%), and knowledge work — but optimized for lower latency. Fast mode pricing is $10/$50 per million input/output tokens, three times cheaper than fast mode for Opus 4.6 and 4.7 ($30/$150). It supports the full 1M token context window and 128k max output tokens.

Choose Opus 4.8 Fast for latency-sensitive agentic pipelines, live coding sessions, and real-time workflows where throughput matters. For cost-sensitive or batch workloads, standard Opus 4.8 offers the same intelligence at half the price.

Context Window 1M

tokens

Max Output 128K

tokens

Input Cost $10

per million tokens

Output Cost $50

per million tokens

Release Date May 27, 2026

 

Try Claude Opus 4.8 Fast for free

Try Claude Opus 4.8 Fast instantly in your browser.
This playground uses the Puter.js AI API — no API keys or setup required.

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Claude Haiku 5.5 is the small, low-cost model in Anthropic's 5.5 family, released on October 7, 2026 and available through the API as anthropic/claude-haiku-5-5. It has a 1M token context window and up to 128k output tokens. Pricing is $0.10 per million input tokens and $0.50 per million output tokens for requests under 100,000 tokens, down from $1 and $5 for Haiku 4.5, and $0.50 and $2.50 above that. Effort levels range from low to max, with medium as the default. Anthropic reports 72.4% on OSWorld 2.1 (offline subset, Haiku 4.5: 15.7%) and 39.2% on Terminal-Bench 4.0 at maximum effort (Haiku 4.5: 0.0%). On the same tests GPT-6 Luna scores 48.9% and 16.4%. It is aimed at summarizing documents, classifying information, querying databases, and handling subtasks for larger agents. Anthropic recommends Opus and Sonnet for demanding coding work.

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Claude Sonnet 5.5

Claude Sonnet 5.5 is a mid-tier model from Anthropic, released on September 28, 2026 and available through the API as anthropic/claude-sonnet-5-5. It accepts text, image, and PDF input, with a 1M token context window and up to 128k output tokens. Pricing is $2 per million input tokens and $10 per million output tokens, the same as Claude Sonnet 5. Anthropic says it generates output more than 30% faster than Sonnet 5 and can cut the cost of a task by up to 30%, because it uses fewer tokens and fewer tool calls. Anthropic reports 70.6% on Terminal-Bench 4.0 (Sonnet 5: 10.3%) and 80.1% on OSWorld 2.1 (Sonnet 5: 57.0%). It is aimed at well-scoped everyday tasks, bug fixing, agentic coding, and producing documents, slides, and spreadsheets.

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Claude Opus 5.5

Claude Opus 5.5 is Anthropic's newest flagship model, released September 22, 2026 as the successor to Claude Opus 5. Anthropic positions it for agentic coding and long-running autonomous work. Reported benchmark scores include 66.4% on Terminal-Bench 4.0 (up from 52.3% for Opus 5), 54.4% on FrontierCode, 40% on AutomationBench (up from 26.9%), 81.8% on the OSWorld 2.0 computer-use benchmark, and 67.7% on Humanity's Last Exam with tools. It runs about 30% faster than Opus 5 and costs roughly 40% less on typical workloads, at $4 per million input tokens and $20 per million output tokens, a 1M-token context window, and 128K max output tokens. That combination of long-horizon coding performance, multimodal input (text, image, PDF), tool calling, and lower cost makes it a fit for developers building coding agents, codebase-wide migrations, and research or analysis pipelines through the API.

Frequently Asked Questions

How do I use Claude Opus 4.8 Fast?

You can access Claude Opus 4.8 Fast by Anthropic through Puter.js AI API. Include the library in your web app or Node.js project and start making calls with just a few lines of JavaScript — no backend and no configuration required. You can also use it with Python or cURL via Puter's OpenAI-compatible API.

Can I try Claude Opus 4.8 Fast for free?

Claude Opus 4.8 Fast is free to try with a Puter account. Every account includes a free AI allowance, and you can chat with it in the playground on this page. You can upgrade your account anytime for a larger allowance.

Is the Claude Opus 4.8 Fast API free for developers?

Claude Opus 4.8 Fast is free to integrate using the Puter.js AI API. With the User-Pays Model, you can add AI to your app for $0, since users cover their own AI usage through their Puter account.

What is the pricing for Claude Opus 4.8 Fast?
Claude Opus 4.8 Fast costs $10 per 1M input tokens and $50 per 1M output tokens.
Price per 1M tokens
Input$10
Output$50
Who created Claude Opus 4.8 Fast?

Claude Opus 4.8 Fast was created by Anthropic and released on May 27, 2026.

What is the context window of Claude Opus 4.8 Fast?

Claude Opus 4.8 Fast supports a context window of 1M tokens. For reference, that is roughly equivalent to 2,000 pages of text.

What is the max output length of Claude Opus 4.8 Fast?

Claude Opus 4.8 Fast can generate up to 128K tokens in a single response.

Does it work with React / Vue / Vanilla JS / Node / etc.?

Yes — the Claude Opus 4.8 Fast 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.

Add Claude Opus 4.8 Fast to your app for free

Developers can integrate Claude Opus 4.8 Fast for free using the Puter.js AI API.
With the User-Pays Model, each user covers their own AI usage instead of the developer.

Get started How pricing works