Claude Opus 4 API

anthropic/claude-opus-4
Claude Opus 4 is Anthropic's most powerful model in the Claude 4 family, built for complex, high-stakes tasks.
Context
200K tokens
Input
$20.631 / 1M tokens
Output
$103.155 / 1M tokens
Released
May 22, 2025

How to use Claude Opus 4 API

Install any OpenAI-compatible SDK, point it at api.aimlapi.com/v1, and set the model to anthropic/claude-opus-4.
import requests

r = requests.post(
    "https://api.aimlapi.com/v1/chat/completions",
    headers={"Authorization": "Bearer " + AIMLAPI_KEY},
    json={
      "model": "anthropic/claude-opus-4",
      "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",
    "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","messages":[{"role":"user","content":"Hello!"}]}'

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

Claude Opus 4 API Pricing

TypePrice
Input
$20.631 / 1M tokens
Output
$103.155 / 1M tokens
Cached input
$2.0631 / 1M tokens

Claude Opus 4 has documented prompt-caching pricing: 5-minute cache writes cost 1.25× base input pricing, 1-hour cache writes cost 2× base input pricing, and cache hits/refreshes are billed at a lower rate.

Claude Opus 4 Benchmarks

BenchmarkScoreWhat it measuresSourceRetrieved
Intelligence
20.6
Composite score across standardised reasoning, knowledge and problem-solving evaluations, measured independently by Artificial AnalysisSourceSeptember 22, 2026
Math
73.3
Composite score across standardised mathematics evaluations, measured independently by Artificial AnalysisSourceSeptember 22, 2026

Claude Opus 4 vs other models

ModelInputOutputContextBest for
Claude Opus 4
This page
$20.631 / 1M tokens
$103.155 / 1M tokens
200K tokens
Agentic workflows and structured output
$4.1262 / 1M tokens
$19.5 / 1M tokens
200K tokens
Chat + assistants
$6.5 / 1M tokens
$32.5 / 1M tokens
200K tokens
Chat + assistants
$6.877 / 1M tokens
$32.5 / 1M tokens
200K tokens
Chat + assistants

Frequently asked questions

Claude Opus 4 has a 200,000 tokens context window and can return up to 32,000 tokens.

Claude Opus 4 takes image, text as input and returns text.

Use anthropic/claude-opus-4 as the model id. Requests go to https://api.aimlapi.com/v1/chat/completions.

Claude Opus 4 became available on May 22, 2025.

Claude Opus 4 is priced at input $20.631 / 1M tokens, output $103.155 / 1M tokens, cached input $2.0631 / 1M tokens.

Yes, Claude Opus 4 can stream responses as they are generated.

Yes, Claude Opus 4 accepts image input alongside text.

Claude Opus 4 was built by Anthropic.

The specifications provided cover Claude Opus 4 only, not Claude Sonnet 4, so no comparison can be given.

It supports reasoning, vision, file input, web search, and tool use, making it suitable for tasks involving text, images, and multi-step tool-assisted workflows.

Yes, it supports parallel tool calls along with structured output formatting.

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