xAI: Grok 4.1 Fast (Reasoning)

Quickstart

Use your Moduck API Key, set the API base URL to https://api.moduck.ai/v1, and set the model parameter to moduck/xai/grok-4-1-fast-reasoning.

import os
import requests

base_url = "https://api.moduck.ai/v1"
api_key = os.environ["MODUCK_API_KEY"]
model_id = "moduck/xai/grok-4-1-fast-reasoning"

response = requests.post(
    f"{base_url}/chat/completions",
    headers={
        "Authorization": f"Bearer {api_key}",
        "Content-Type": "application/json",
    },
    json={
        "model": model_id,
        "messages": [{"role": "user", "content": "Hello!"}],
        "stream": False,
    },
    timeout=60,
)
response.raise_for_status()
print(response.json())

Use the familiar OpenAI-style chat request format to make model integration easier.

Grok 4.1 Fast (Reasoning) API Pricing

Performance

Measured on the Moduck gateway across live traffic, hour by hour over the last 24 hours. Time to first token is how long before anything appears; throughput is how fast the answer is written after that; end-to-end latency is the whole round trip. Figures are medians unless the card says otherwise.

Availability

Uptime is the share of time at least one provider serving this model responded. Availability is stricter: the share of requests actually served. A provider that answers but fails part of the traffic lowers availability without lowering uptime. Both cover the last three days.

Grok 4.1 Fast (Reasoning) Compare models

Model specifications

Input

text, image

Output

text

Context window

2,000,000

Maximum output

30,000

Release date

2025-11-19

Attachments

Yes

Reasoning

Yes

Tool calling

Yes

Structured output

Yes

Temperature setting

Yes

Open weights

No

Frequently asked questions

Related models

Grok 4.6xAIInputUSD 1.6 / 1M tokensOutputUSD 4.8 / 1M tokensView modelGrok 4.5xAIInputUSD 1.6 / 1M tokensOutputUSD 4.8 / 1M tokensView modelGrok 4.1 FastxAIInputUSD 0.16 / 1M tokensOutputUSD 0.4 / 1M tokensView model