Model Tracker
Grok 4.1 Fast
Grok 4.1 Fast is an AI model made by xAI. xAI released it on 19 November 2025. xAI retired it on 15 May 2026. Its context window is 2,000,000 tokens.
- Released
- 19 November 2025 — x.ai, read 16 October 2026
- Status
- Not confirmed: two readings disagree: retired and ga
- Takes
- Not confirmed: The maker's pages checked do not state the model's input modalities.
- Returns
- Not confirmed: The maker's pages checked do not state the model's output modalities.
- Open weights
- Not confirmed: The maker's pages checked do not state whether the model's weights are open or downloadable.
- Licence
- Not confirmed: The maker's pages checked do not name a licence for this model.
- Context window
- 2,000,000 tokens — x.ai, read 16 October 2026
- Longest answer
- Not confirmed: The maker's pages checked do not print the model's standard maximum output-token limit.
- Knowledge cutoff
- Not confirmed: The maker's pages checked do not state a knowledge-cutoff date for this model.
- API price, input
- Not confirmed: The current official API pricing page does not list this retired model. The launch announcement gives an input price, but it is not the maker's pricing page, so it is not entered as a register price.
- API price, output
- Not confirmed: The current official API pricing page does not list this retired model. The launch announcement gives an output price, but it is not the maker's pricing page, so it is not entered as a register price.
- Where
- Not confirmed: The maker says the model was retired from the API and that requests to its former model slugs redirect to Grok 4.3. The pages checked do not confirm current availability of Grok 4.1 Fast itself on any listed channel.
- Parameters
- Not confirmed: The maker's pages checked do not publish a parameter count for this model.
- Model card
- Not confirmed: No maker-published model card or system card for Grok 4.1 Fast was found on the pages checked.
Benchmarks
Measured by others, not by the maker: each score with the name the measurer gives the model and the setting it ran, its day and its licence.
Arena
- Text Arena, grok-4-1-fast-reasoning: 1,430 (1,427–1,434, 57,541 votes), published 15 October 2026
- Code Arena (WebDev), Grok 4.1 Fast (Reasoning): 1,242 (1,231–1,253, 5,490 votes), published 18 October 2026
- Vision Arena, grok-4-1-fast-reasoning: 1,196 (1,189–1,203, 13,373 votes), published 9 October 2026
Arena’s leaderboard dataset (lmarena-ai/leaderboard-dataset on Hugging Face), CC BY 4.0: ratings from people’s votes between two anonymous models, as Arena publishes them. Data · CC BY 4.0
Questions
When was Grok 4.1 Fast released?
xAI released Grok 4.1 Fast on 19 November 2025.
What is the context window of Grok 4.1 Fast?
The context window of Grok 4.1 Fast is 2,000,000 tokens, as xAI prints it.
More from xAI
- Grok 3
- Grok 3 (Think)
- Grok 3 mini
- Grok 3 mini (Think)
- Grok 4
- Grok 4 Fast
- Grok 4 Heavy
- Grok 4.1
- Grok 4.20
- Grok 4.20 Multi-Agent Beta
- Grok 4.3
- Grok 4.5
- Grok 4.6
- Grok 4.7
- Grok Build 0.1
- Grok Code Fast 1
- Grok Imagine Image 2.0
- Grok Imagine Video 1.5
- Grok Voice 1.0
- Grok Voice 2.0
- Grok Voice 3.0
- Grok-1
- Grok-1.5V
- Grok-2
Sources
- Grok 4.1 Fast and Agent Tools API (read 16 October 2026)
- Grok Model Retirement on May 15, 2026 (read 16 October 2026)
- Pricing (read 16 October 2026)
- Models (read 16 October 2026)