> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cdn-fly.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Grok 4.1 Fast Reasoning

> Call xAI Grok 4.1 Fast Reasoning via Starrise AI API. Grok 4.1 reasoning variant.

Grok 4.1 Fast Reasoning is xAI's language model, available through Starrise AI. Grok 4.1 reasoning variant.

## Key Capabilities

* **OpenAI-compatible** — Use directly with the OpenAI SDK
* **Streaming** — Supports real-time SSE streaming
* **Strong reasoning** — Suitable for complex, multi-step tasks

## Quick Example

```bash cURL theme={null}
curl https://dayu.cdn-fly.com/v1/chat/completions \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "grok-4-1-fast-reasoning",
    "messages": [
      { "role": "user", "content": "Explain quantum entanglement in simple terms." }
    ]
  }'
```

```python Python theme={null}
from openai import OpenAI

client = OpenAI(
    api_key="YOUR_API_KEY",
    base_url="https://dayu.cdn-fly.com/v1"
)

response = client.chat.completions.create(
    model="grok-4-1-fast-reasoning",
    messages=[
        {"role": "user", "content": "Explain quantum entanglement in simple terms."}
    ]
)

print(response.choices[0].message.content)
```

## Parameters

| Parameter | Type | Required | Description |
| - | - | - | - |
| `model` | string | Yes | Fixed value: `grok-4-1-fast-reasoning` |
| `messages` | array | Yes | List of `{ role, content }` objects |
| `max_tokens` | integer | No | Maximum number of tokens to generate |
| `temperature` | float | No | `0`–`2`, controls randomness, default `1` |
| `stream` | boolean | No | Enable SSE streaming, default `false` |
| `top_p` | float | No | Nucleus sampling threshold |

> **[API Reference](/en/api-reference/model-api/xai/grok-4-1-fast-reasoning)**
>
> View the interactive API Playground for Grok 4.1 Fast Reasoning.


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