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
2M
Released
Sep 19, 2025
Knowledge Cutoff
Sep 2025
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. Reasoning can be enabled/disabled using the reasoning enabled parameter in the API. Learn more in our docs
Grok 4 Fast has a 2,000,000 token context window.
Grok 4 Fast accepts text, images and files such as PDFs as input and returns text.
Grok 4.6, Grok 4.5, Grok Build 0.1 and 3 more are other text models from SpaceXAI.
Grok 4 Fast was released on September 19, 2025. Its knowledge cutoff is September 30, 2025.
Token volume and request traffic to this model over time.