xAI
LLM
Light
Closed weights
Grok 4.1 Fast
358 days since xAI announced it ·
Grok 4.1 Fast is a closed-weights LLM from xAI, announced 19 Nov 2025. It costs $0.20 per 1M input tokens and $0.50 per 1M output tokens. Its context window is 2M tokens.
- Input
- $0.20
- per 1M tokens
- Cache write
- —
- per 1M tokens
- Cache read
- $0.05
- per 1M tokens
- Output
- $0.50
- per 1M tokens
- Context window
- 2M
- tokens
- Parameters
- —
- not disclosed
- Announcement
- x.ai/news/grok-4-1-fast
Our coverage
We haven’t written about Grok 4.1 Fast yet.
xAI · Light
closed weights- Grok 4.1 Fast
More from xAI
All modelsFacts last updated , from xAI’s own pages.