Released Sep 19, 2025Knowledge cutoff Sep 30, 20252,000,000 context
Starting at $0.20/M input tokensStarting at $0.50/M output tokens$5/K web search
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 reasoningenabled parameter in the API. Learn more in our docs