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xAI: Grok 4.1 Fast

by xAI

Grok 4.1 Fast is xAI's best agentic tool calling model that shines in real-world use cases like customer support and deep research. 2M context window. Reasoning can be enabled/disabled using the `reasoning` `enabled` parameter in the API. [Learn more in our docs](https://openrouter.ai/docs/use-cases/reasoning-tokens#controlling-reasoning-tokens)

Avg Score

81.4%

386 answers

Avg Latency

14.2s

74 runs

Pricing

$0.20

input

/

$0.50

output

per 1M tokens

Context

2000K

tokens

Alternatives

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Same Quality, Cheaper

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Same Quality, Faster

Models with similar or better performance but lower latency.

Same Cost, Better

Models at a similar price point with higher benchmark scores.

No alternatives found

Other Models from xAI

Compare performance with other models from the same creator

ModelScoreLatencyCost/1M
xAI: Grok 393.8%24.7s$9.00
xAI: Grok 3 Mini Beta93.8%23.3s$0.40
xAI: Grok 3 Beta91.7%26.8s$9.00
xAI: Grok Code Fast 189.2%16.1s$0.85
xAI: Grok 3 Mini87.7%22.0s$0.40
xAI: Grok 481.2%43.0s$9.00
xAI: Grok 4 Fast79.3%18.3s$0.35

Benchmark Performance

How this model performs across different benchmarks

Price vs Performance

Compare cost efficiency across all models

Current model (baseline)
Other models (relative score)
Y-axis shows score difference from shared benchmarks. X-axis uses log scale.

Score Over Time

Performance trends across all benchmark runs

Benchmark Activity

Number of benchmark runs over time

Quickstart

Get started with this model using OpenRouter

View on OpenRouter
import { OpenRouter } from "@openrouter/sdk";

const openrouter = new OpenRouter({
  apiKey: "<OPENROUTER_API_KEY>"
});

const completion = await openrouter.chat.completions.create({
  model: "x-ai/grok-4.1-fast",
  messages: [
    {
      role: "user",
      content: "Hello!"
    }
  ]
});

console.log(completion.choices[0].message.content);

Get your API key at openrouter.ai/keys