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...
- 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 tokens | Provider | + 3% fee | You 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
| Category | Elo | Win rate | Rank |
|---|---|---|---|
| 3Dmodels | 1289 | 59.9% | #19 |
| ASCII artmodels | 1240 | 55.7% | #11 |
| Codemodels | 1292 | 60% | #17 |
| Data vizmodels | 1284 | 58.7% | #14 |
| Game devmodels | 1295 | 59.5% | #18 |
| SVGmodels | 1236 | 58.6% | #16 |
| UI componentsmodels | 1296 | 59.3% | #15 |
| Websitesmodels | 1290 | 60.1% | #17 |
| androidnativeagents | 1190 | 65.5% | #13 |
| Full-stackagents | 1224 | 59.9% | #9 |
| Mobile appsagents | 1240 | 57.5% | #6 |
| Web appsagents | 1221 | 54.2% | #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.
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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