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Claude Opus 4.5

AnthropicReleased Nov 24, 2025

Claude Opus 4.5 is Anthropic’s frontier reasoning model optimized for complex software engineering, agentic workflows, and long-horizon computer use. It offers strong multimodal capabilities, competitive performance across real-world coding and...

Try in playground
Context window
200K tokens
Max output
64K tokens
Input
file, image, text
Output
text
Tokenizer
Claude
Released
Nov 24, 2025
Reasoning
optional

Pricing

Per 1M tokens. The provider price and our flat 3% fee are separate columns — what you pay is their sum.

Per 1M tokensProvider+ 3% feeYou pay
Input$5.00$0.150$5.15
Output$25.00$0.750$25.75
Cache read$0.500$0.015$0.515
Cache write$6.25$0.188$6.44

Benchmarks

Design Arena

CategoryEloWin rateRank
3Dmodels128959.9%#19
ASCII artmodels124055.7%#11
Codemodels129260%#17
Data vizmodels128458.7%#14
Game devmodels129559.5%#18
SVGmodels123658.6%#16
UI componentsmodels129659.3%#15
Websitesmodels129060.1%#17
androidnativeagents119065.5%#13
Full-stackagents122459.9%#9
Mobile appsagents124057.5%#6
Web appsagents122154.2%#11

Head-to-head preference voting. How we filter and rank

Supported parameters

  • include_reasoning
  • max_tokens
  • reasoning
  • response_format
  • stop
  • structured_outputs
  • temperature
  • tool_choice
  • tools
  • top_k
  • verbosity

Call it

OpenAI-compatible: point your SDK at api.openkey.ai/v1 and use model anthropic/claude-opus-4.5.

Code sample language
curl https://api.openkey.ai/v1/chat/completions \
  -H "Authorization: Bearer $OPENKEY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "anthropic/claude-opus-4.5",
    "messages": [{"role": "user", "content": "Hello"}]
  }'
import os
from openai import OpenAI

client = OpenAI(
    base_url="https://api.openkey.ai/v1",
    api_key=os.environ["OPENKEY_API_KEY"],
)

completion = client.chat.completions.create(
    model="anthropic/claude-opus-4.5",
    messages=[{"role": "user", "content": "Hello"}],
)
print(completion.choices[0].message.content)
import OpenAI from "openai";

const client = new OpenAI({
  baseURL: "https://api.openkey.ai/v1",
  apiKey: process.env.OPENKEY_API_KEY,
});

const completion = await client.chat.completions.create({
  model: "anthropic/claude-opus-4.5",
  messages: [{ role: "user", content: "Hello" }],
});
console.log(completion.choices[0].message.content);

Questions

How much does Claude Opus 4.5 cost via API?
Through OpenKey, Claude Opus 4.5 costs $5.15 per 1M input tokens and $25.75 per 1M output tokens. That is the provider price ($5.00 / $25.00) plus a flat 3% fee — nothing else.
What is Claude Opus 4.5's context window?
Claude Opus 4.5 accepts up to 200K tokens of context and returns up to 64K tokens per request.
Is Claude Opus 4.5 OpenAI-compatible?
Yes. Send requests to OpenKey's /v1/chat/completions endpoint with model "anthropic/claude-opus-4.5" using any OpenAI SDK — only the base URL and API key change.
What inputs does Claude Opus 4.5 support?
Claude Opus 4.5 accepts file, image, text input and produces text output.

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