Grok Fast
xAI · lightweight line
Latest: Grok 4.1 Fast · Nov 19, 2025
DiscontinuedOfficially discontinued on May 15, 2026
Days since last release
Days since last release
339
days
Recent gaps
Recent gaps
Grok 4.1 Fast · Nov 2025
61
Grok 4 Fast
xAI · Grok Fast line · lightweight
Grok 4 Fast was released by xAI on September 19, 2025, as a lightweight model in the Grok Fast line.
- Release 1 of 2 in the Grok Fast line.
- The first release in this line.
- Replaced by Grok 4.1 Fast on November 19, 2025, 61 days later.
No detailed card for this model: we only add numbers published by the maker or by independent benchmarks.
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Where the Grok Fast line stands
Grok 4.1 Fast is the current model in this line. The card shows how long it has been since the last release against the line's usual gap and its recent ones — the rhythm, not a date.
Every Grok Fast release
Newest first. See the full line with every card →
- Nov 19, 2025Grok 4.1 Fast
- Sep 19, 2025Grok 4 Fast · this page