Grok 4.1 Fast
Grok 4.1 Fast is an API-only (closed weights) language model from xAI, released November 19, 2025.
Today, we’re excited to launch two powerful new additions to the xAI API: Grok 4.1 Fast, our best tool-calling model with a 2M context window. It reasons and completes agentic tasks accurately and rapidly, excelling at complex real-world use cases such as customer support and finance.
Check it against your own PC →
Lab
xAI
Released
November 19, 2025
Weights
API-only (closed weights)
Parameters
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Context
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Price / M tokens
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Epoch ECI
not yet rated
Benchmark results
Epoch AI has not published results for Grok 4.1 Fast yet. New models are usually evaluated within days to weeks.
Links
More from xAI
Grok 4.7 · Grok 4.6 · Grok 4.5 · Grok 4.3 Beta · Grok Build 0.1 · Grok 4.20 Multi-Agent · Grok 4.20 · Grok 4.1