Question 1

What is Grok 4.1 Fast?

Accepted Answer

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)

Question 2

What is the context length of Grok 4.1 Fast?

Accepted Answer

Grok 4.1 Fast has a 2,000,000 token context window.

Question 3

What inputs and outputs does Grok 4.1 Fast support?

Accepted Answer

Grok 4.1 Fast accepts text, images and files such as PDFs as input and returns text.

Question 4

What other text models does SpaceXAI have?

Accepted Answer

Grok 4.5, Grok Build 0.1, Grok 4.3 and 2 more are other text models from SpaceXAI.

Question 5

When was Grok 4.1 Fast released?

Accepted Answer

Grok 4.1 Fast was released on 2025-11-19.

xAI: Grok 4.1 Fast

x-ai/grok-4.1-fast

xAI: Grok 4.1 Fast

x-ai/grok-4.1-fast

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