Claude Opus 4.8 (Fast) API

Claude Opus 4.8 Fast is a high-speed configuration of Anthropic’s Claude Opus 4.8 model, designed to produce output about 2.5× faster in fast mode.
Context
1M tokens
Input
$13 / 1M
Output
$65 / 1M
Released
May 27, 2026

How to use Claude Opus 4.8 (Fast) API

Install any OpenAI-compatible SDK, point it at api.aimlapi.com/v1, and set the model to anthropic/claude-opus-4.8-fast.

import requests

r = requests.post(
   "https://api.aimlapi.com/v1/chat/completions",
   headers={"Authorization": "Bearer " + AIMLAPI_KEY},
   json={
     "model": "anthropic/claude-opus-4.8-fast",
     "messages": [
       {
         "role": "user",
         "content": "Hello!"
       }
     ]
   },
)
print(r.json())

const r = await fetch("https://api.aimlapi.com/v1/chat/completions", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.AIMLAPI_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "model": "anthropic/claude-opus-4.8-fast",
    "messages": [
      {
        "role": "user",
        "content": "Hello!"
      }
    ]
  }),
});
console.log(await r.json());
curl -X POST https://api.aimlapi.com/v1/chat/completions \
  -H "Authorization: Bearer $AIMLAPI_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"anthropic/claude-opus-4.8-fast","messages":[{"role":"user","content":"Hello!"}]}'

OpenAI-compatible — swap the base URL and it works with your existing SDK.

Claude Opus 4.8 (Fast) API Pricing

TypePrice
Input
$13 / 1M
Output
$65 / 1M
Cached input
$1.3 / 1M

Fast mode for Claude Opus 4.8 is a research preview, is available only on the Claude API (first-party), and its pricing stacks with prompt caching and data residency multipliers; it is not available with the Batch API.

Claude Opus 4.8 (Fast) vs other models

ModelInputOutputContextBest for
$13 / 1M
$65 / 1M
1M tokens
Agentic workflows and structured output
$6.5 / 1M
$32.5 / 1M
1M tokens
Complex agentic coding and enterprise workflows
$6.5 / 1M
$32.5 / 1M
1M tokens
Chat + assistants
$13 / 1M
$65 / 1M
1M tokens
Chat + assistants

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