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    • © 2026 OpenRouter, Inc

    xAI: Grok 4.1 Fast

    x-ai/grok-4.1-fast

    Created Nov 19, 20252,000,000 context

    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

    Recent activity on Grok 4.1 Fast

    Total usage per day on OpenRouter

    Prompt
    7.99B
    Reasoning
    766M
    Completion
    319M

    Prompt tokens measure input size. Reasoning tokens show internal thinking before a response. Completion tokens reflect total output length.