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xAI: Grok 4 Fast

x-ai/grok-4-fast

Grok 4 Fast is xAI's latest multimodal model with SOTA cost-efficiency and a 2M token context window. It comes in two flavors: non-reasoning and reasoning. Read more about the model on xAI's news post(opens in new tab).

Reasoning can be enabled/disabled using the reasoning enabled parameter in the API. Learn more in our docs(opens in new tab)

Modalities

Context

High

2M

Released

Sep 19, 2025

Knowledge Cutoff

Sep 2025

Activity

Activity

Token volume and request traffic to this model over time.