Claude Sonnet 5.5 · API

OpenAI-compatible chat completions backed by Anthropic Claude Sonnet 5.5, the newest Sonnet and the best combination of speed and intelligence: a 1M-token context window, up to 128K output tokens per request and adaptive thinking. Image input, tool calling, prompt caching, stop sequences and streaming are supported; set model to claude-sonnet-5-5. On the OpenAI-compatible endpoint the model thinks at its default effort and returns no thinking content, and response_format is not guaranteed. For effort control (output_config.effort: low / medium / high / xhigh / max), thinking summaries (thinking.display: summarized), structured output (output_config.format) or PDF input, use the native Anthropic Messages API at /anthropic/v1/messages, which Claude Code connects to directly. temperature / top_p / top_k are ignored, a forced tool choice is treated as auto, and thinking set to disabled is ignored.

📥 Context window (max input)：1,000,000 tokens (Anthropic published figure); up to 128,000 output tokens per request.

Authorization: Bearer YOUR_API_KEY
Content-Type: application/json

curl https://nezhagate.com/v1/chat/completions -H "Authorization: Bearer YOUR_API_KEY" -H "Content-Type: application/json" -d '{"model": "claude-sonnet-5-5", "messages": [{"role": "user", "content": "Hello"}], "stream": false}'

from openai import OpenAI

client = OpenAI(api_key="YOUR_API_KEY", base_url="https://nezhagate.com/v1")
res = client.chat.completions.create(
    model="claude-sonnet-5-5",
    messages=[{"role": "user", "content": "Hello"}],
)
print(res.choices[0].message.content)

import OpenAI from "openai";

const client = new OpenAI({ apiKey: "YOUR_API_KEY", baseURL: "https://nezhagate.com/v1" });
const res = await client.chat.completions.create({
  model: "claude-sonnet-5-5",
  messages: [{ role: "user", content: "Hello" }],
});
console.log(res.choices[0].message.content);

{
  "id": "chatcmpl_xxx",
  "object": "chat.completion",
  "model": "claude-sonnet-5-5",
  "choices": [
    {"index": 0, "message": {"role": "assistant", "content": "Hello!"}, "finish_reason": "stop"}
  ],
  "usage": {"prompt_tokens": 11, "completion_tokens": 7, "total_tokens": 18}
}

curl https://nezhagate.com/v1/chat/completions -H "Authorization: Bearer YOUR_API_KEY" -H "Content-Type: application/json" -d '{"model": "claude-sonnet-5-5", "messages": [{"role": "user", "content": [{"type": "text", "text": "What is in this picture?"}, {"type": "image_url", "image_url": {"url": "https://example.com/photo.jpg"}}]}]}'