xAI: Grok 4 Fast

x-ai/grok-4-fast

Created Sep 19, 20252,000,000 context

Starting at $0.20/M input tokensStarting at $0.50/M output tokens

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

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xAI: Grok 4 Fast

x-ai/grok-4-fast

Created Sep 19, 20252,000,000 context

Starting at $0.20/M input tokensStarting at $0.50/M output tokens

Reasoning can be enabled/disabled using the reasoning enabled parameter in the API. Learn more in our docs

Recent activity on Grok 4 Fast

Total usage per day on OpenRouter

Prompt

14.7B

Reasoning

1.49B

Completion

1.15B

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

xAI: Grok 4 Fast – Recent Activity and Usage Stats | OpenRouter