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xAI: Grok 4.1 Fast

x-ai/grok-4.1-fast

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(opens in new tab)

Modalities

Context

2M

Weekly Tokens

434B

Released

Nov 19, 2025

Activity