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AnthropicText Generation/v1/ai/chat

Claude Opus 4.6 Fast

Access Claude Opus 4.6 Fast through one API key. Fastest Opus with 128K output.

Anthropic's fastest Opus variant. Same intelligence as Opus 4.6 with faster output and 128K output tokens.

No credit card required. Takes 30 seconds.

2,400+

Developers

1.2M+

API calls served

100+

Endpoints

$0.01

Per call

Yep, that's it.

Try it live

Send a message and see Claude Opus 4.6 Fast respond in real time.

POST/v1/ai/chat

Maximum tokens in the response.

Real-time tokens

Hit "Send Request" to see the response

Context Window

1M tokens

Max Output

128K tokens

Input Price

$42.00 / 1M tokens

Output Price

$210.00 / 1M tokens

Strengths

Opus-level intelligence

Claude Opus 4.6 Fast delivers the same intelligence as Opus 4.6, keeping top-tier reasoning and writing quality.

Faster output

This variant is tuned for quicker generation than standard Opus, reducing latency for interactive and long-output tasks.

128K output tokens

Up to 128,000 output tokens per response support very long documents, detailed designs, and large generations.

1M context

A 1,000,000-token context window lets it reason over entire codebases, large document sets, and long histories at once.

Quick start

Copy this snippet and start making calls with Claude Opus 4.6 Fast.

const res = await fetch('https://api.yepapi.com/v1/ai/chat', {
  method: 'POST',
  headers: {
    'x-api-key': 'YOUR_API_KEY',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    "model": "anthropic/claude-opus-4.6-fast",
    "messages": [
      {
        "role": "user",
        "content": "Explain API gateways in 2 sentences."
      }
    ],
    "maxTokens": 256
  }),
});
const { data } = await res.json();
console.log(data.message.content);

Why use Claude Opus 4.6 Fast through YepAPI?

One API key for all models — no separate accounts
OpenAI SDK compatible — just change the base URL
No monthly minimums — pay per token
Switch models with one line of code
Full provider passthrough — citations, search results, and all extras included
Streaming and non-streaming support on every model
Works with Cursor, Claude, LangChain, and any LLM tool
Unified billing across all providers

Claude Opus 4.6 Fast API: fastest Opus with 128K output

Claude Opus 4.6 Fast is Anthropic's fastest Opus variant, delivering the same intelligence as Opus 4.6 with quicker output. It pairs a 1M-token context window with up to 128K output tokens, and is priced as a premium model at $42.00 per 1M input tokens and $210.00 per 1M output tokens.

Through YepAPI you access Claude Opus 4.6 Fast with one OpenAI-compatible API key. That key also reaches more affordable models for routine work, plus SEO, SERP, and web-scraping endpoints, so you can reserve Opus for your hardest, highest-value tasks.

What is Claude Opus 4.6 Fast?

Claude Opus 4.6 Fast is Anthropic's speed-tuned Opus variant: it keeps the full intelligence of Claude Opus 4.6 while generating output more quickly, reducing latency on long or interactive tasks. It carries a 1,000,000-token context window and can produce up to 128,000 output tokens, so it reasons over entire codebases or large document sets and returns very long, structured results in one pass. As a top-tier model it is priced as a premium option at $42.00 per 1M input and $210.00 per 1M output tokens, reflecting Opus-class capability with faster delivery.

Build with Claude Opus 4.6 Fast via YepAPI

Send requests to the OpenAI-compatible /v1/ai/chat endpoint with your YepAPI key. The standard Chat Completions schema lets you call this Anthropic model from existing SDKs by changing the base URL and model name. Use it for demanding work — deep technical writing, complex analysis, and large code reasoning — where you want Opus quality with less waiting. One key also covers cheaper models plus SEO, SERP, and scraping APIs, so you can route only the hardest tasks here and keep costs controlled.

Claude Opus 4.6 Fast API pricing — $42.00 / $210.00 per 1M tokens

Claude Opus 4.6 Fast costs $42.00 per 1M input tokens and $210.00 per 1M output tokens, premium pricing for top-tier intelligence with faster output. Because it can both ingest up to 1M tokens and emit up to 128K, it is best reserved for high-value tasks that justify the rate. With one YepAPI key you can send only those tasks to Opus and bill routine work to cheaper models, keeping spend in check.

Claude Opus 4.6 Fast for long technical documents

The model excels at demanding long-form work: comprehensive technical design documents, large code reasoning across a whole repository, and detailed analyses where both deep intelligence and quick turnaround matter. The 1M context lets it hold all the source material at once, the 128K output gives room for thorough results, and the speed tuning keeps long generations from dragging. It is built for high-stakes tasks where Opus quality is required but latency still counts.

Try Claude Opus 4.6 Fast free

New YepAPI accounts include $5 in free credit with no card required. That lets you put a genuinely hard task to Claude Opus 4.6 Fast and judge both its quality and its speed before relying on the premium tier.

Start generating in 30 seconds

$5 free credit on signup. No credit card required. Pay per call.

What developers say

Switched from SerpAPI and cut our SERP costs by 80%. Same data quality, way simpler billing.

Marcus T.

SEO Platform Founder

One API key for AI models, SERP data, and web scraping. Saved us from managing 4 separate providers.

Priya S.

Full-Stack Developer

The $5 free credit let us prototype our entire rank tracking feature before committing. No other API does that.

Jake R.

Indie Hacker

Frequently asked questions

Anthropic's fastest Opus variant. Same intelligence as Opus 4.6 with faster output and 128K output tokens.

Input tokens cost $42.00 per 1M tokens and output tokens cost $210.00 per 1M tokens through YepAPI. No monthly minimums — you only pay for what you use.

Sign up for a free API key, then send requests to the /v1/ai/chat endpoint.

Claude Opus 4.6 Fast supports a 1M token context window with up to 128K output tokens per request.

Ready to use Claude Opus 4.6 Fast?

$5 free credit on signup. No credit card required. Pay per call.

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