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Grok 4.1 Fast (Non-Reasoning)

Retired May 2026

Non-reasoning variant of Grok 4.1 Fast, released November 2025, sharing unified weights with the reasoning variant and prompt-steered for low-latency responses with fewer hallucinations.

Context
2M tokens
Cutoff
Released
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Capabilities

What Grok 4.1 Fast (Non-Reasoning) accepts and can do, as published by xAI.

  • Text Accepts and generates natural-language text.
  • Image Accepts images as input alongside text.
  • Function calling Connect to external tools, APIs, and systems.
  • Structured output Return responses in structured formats like JSON.

Common questions

What is Grok 4.1 Fast (Non-Reasoning) good for?

Low-latency responses without a reasoning step, which suited document parsing and extraction at volume. It took text and images, and xAI says it hallucinated less than the models before it.

When is Grok 4.1 Fast (Non-Reasoning) not a good fit?

Any new work: xAI retired it in May 2026, and its migration guide points to Grok 4.3 with reasoning effort set to none. No built-in web search or code execution, and closed weights.

How does Grok 4.1 Fast (Non-Reasoning) compare with Grok 4 Fast (Non-Reasoning)?

xAI says Grok 4.1 Fast (Non-Reasoning) got long-horizon reinforcement learning in simulated tool environments across dozens of domains, with a focus on multi-turn agent work, and hallucinates much less than Grok 4 Fast (Non-Reasoning). It launched with xAI's Agent Tools API. Same 2M-token context and text and image input. Grok 4.1 Fast (Non-Reasoning) came out 2 months later.

Can I self-host Grok 4.1 Fast (Non-Reasoning)?

No. xAI does not publish the weights; Grok 4.1 Fast (Non-Reasoning) is available only through hosted APIs.

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