Claude Opus 4.1 API

anthropic/claude-opus-4.1
Claude Opus 4.1 from Anthropic is a powerful AI model optimized for coding, reasoning, and autonomous workflows.
Context
200K tokens
Input
$20.631 / 1M tokens
Output
$103.155 / 1M tokens
Released
Aug 5, 2025

How to use Claude Opus 4.1 API

Install any OpenAI-compatible SDK, point it at api.aimlapi.com/v1, and set the model to anthropic/claude-opus-4.1.
import requests

r = requests.post(
    "https://api.aimlapi.com/v1/chat/completions",
    headers={"Authorization": "Bearer " + AIMLAPI_KEY},
    json={
      "model": "anthropic/claude-opus-4.1",
      "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-4.1",
    "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-4.1","messages":[{"role":"user","content":"Hello!"}]}'

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

Claude Opus 4.1 API Pricing

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

Claude Opus 4.1 Benchmarks

BenchmarkScoreWhat it measuresSourceRetrieved
Tau-bench
56%
Tool-use agents in realistic customer-service tasksSourceJuly 8, 2026
AIME 2025
78%
Competition mathematics (AIME), 2025SourceJuly 8, 2026
GPQA Diamond
80.9%
Google-proof graduate science questions (hardest subset)SourceJuly 8, 2026
SWE-bench Verified
74.5%
Resolving verified real GitHub issuesSourceJuly 8, 2026
Intelligence
22.8
Composite score across standardised reasoning, knowledge and problem-solving evaluations, measured independently by Artificial AnalysisSourceSeptember 22, 2026
Math
80.3
Composite score across standardised mathematics evaluations, measured independently by Artificial AnalysisSourceSeptember 22, 2026

Claude Opus 4.1 vs other models

ModelInputOutputContextBest for
$20.631 / 1M tokens
$103.155 / 1M tokens
200K tokens
Chat + assistants
$6.5 / 1M tokens
$39 / 1M tokens
1M tokens
Reasoning + agents
$2.6 / 1M tokens
$13 / 1M tokens
1M tokens
Balanced coding + agents
$3.9 / 1M tokens
$19.5 / 1M tokens
1M tokens
Long-context, multimodal & agentic workflows
$1.95 / 1M tokens
$11.7 / 1M tokens
1M tokens
Reasoning + agents

Frequently asked questions

Claude Opus 4.1 has a 200,000 tokens context window and can return up to 32,000 tokens.

Claude Opus 4.1 takes text as input and returns text.

Use anthropic/claude-opus-4.1 as the model id. Requests go to https://api.aimlapi.com/v1/chat/completions.

Claude Opus 4.1 is priced at input $20.631 / 1M tokens, output $97.5 / 1M tokens, cached input $2.0631 / 1M tokens.

Yes, Claude Opus 4.1 can stream responses as they are generated.

Claude Opus 4.1 was built by Anthropic.

Start building with Claude Opus 4.1

Get API Key
1000+ models, one API.