Grok 4.1 Fast
No estimate
No hardware requirements for this model
The weights for this model have not been published, so it cannot be downloaded or run on your own hardware at any size. It is reachable only through its provider, and no graphics card changes that.
On record
Full specification
Everything on record for this model. Most of it describes how it was trained rather than how it runs — useful context for judging how much work went into it, and how it compares with models built at a different scale.
Origin
Who built this model, where, and when it was published.
- Organisation
- xAI
- Organisation type
- Industry
- Country
- United States of America
- Published
- 19 November 2025
What it does
The problem areas the model was built for. A model can carry several of each.
- Domain
- Language
- Task
- Language modeling/generation, Question answering, Mathematical reasoning, Quantitative reasoning, Code generation
Size
How large the model is and how much data it was trained on. Parameters are the figure that decides whether it fits on a given graphics card.
- Training data
- tokens
Availability
Whether you can obtain the model and run it on your own hardware, which is what decides if any of the graphics-card figures on this page apply.
- Weights
- Closed — provider access only
- Model access
- API access
- Training code
- Unreleased
How it is classified
Labels the source dataset applies when tracking notable models, and how confident it is in the entry.
- Why it is tracked
- SOTA improvement
- Record confidence
- Unknown
Briefly SOTA on tau-bench
Sources
Where this record came from and when it was last checked.
- Reference
- Grok 4.1 Fast and Agent Tools API
- Last updated
- 24 April 2026
What the numbers mean
What this model is
Grok 4.1 Fast was published by xAI, in United States of America, in November 2025. The organisation is categorised as industry.
It works in Language, and is recorded as doing language modeling/generation, Question answering, Mathematical reasoning, Quantitative reasoning, Code generation.
This is a closed model: the trained values stayed with whoever produced them, and there is no local version to run.
How it was trained
Its inclusion criterion is sOTA improvement.
Answers
Grok 4.1 Fast — common questions
Who created Grok 4.1 Fast?
Grok 4.1 Fast was published by xAI, based in United States of America, categorised as industry.
When was Grok 4.1 Fast released?
Grok 4.1 Fast was published in November 2025.
What is Grok 4.1 Fast used for?
Grok 4.1 Fast works in Language, and is recorded as handling language modeling/generation, Question answering, Mathematical reasoning, Quantitative reasoning, Code generation. Models frequently carry more than one of each, and the tags describe purpose rather than capability limits.
What GPU do I need to run Grok 4.1 Fast?
None. Grok 4.1 Fast is a closed model — its weights were never published, so it cannot be downloaded or run on your own hardware at any price. It is reachable only through its provider.
Is Grok 4.1 Fast open source?
No. Grok 4.1 Fast has not had its weights published, so it exists only as a service controlled by its owner.
How many parameters does Grok 4.1 Fast have?
No parameter count has been published for Grok 4.1 Fast, which is why no memory or speed figure appears on this page.
The other direction
Looking at it from the other side?
This page starts from the model. If you already own a card and want to know everything it will run, start from the hardware instead.