Grok 4.1 Fast
by xAI
· GROK 4 family · released Sep 8, 2025
Closed
Active
xAI's cost-efficient reasoning model that approaches Grok 4.1 quality at roughly 1/7th the price, with a 2M-token context window. It was made free for all users on X and the API for a limited period after launch.
Pricing
Launch price (from Sep 8, 2025)
$0.200 in / $0.500 out per 1M tokens
Current price (since Sep 8, 2025)
$0.200 in / $0.500 out per 1M tokens
| Tier | Effective | In $/M | Out $/M | Cache $/M | Per image | Per second | Source |
|---|---|---|---|---|---|---|---|
| Standard | Sep 8, 2025 – now | $0.200 | $0.500 | - | - | - | - |
Specifications
| Model type | Multimodal |
|---|---|
| Architecture | Unknown |
| Parameters | Not disclosed |
| Context window | 2M tokens |
| Max output | Not disclosed tokens |
| Knowledge cutoff | Not disclosed |
| License | Proprietary |
| Modalities | Text input Image input Text output |
| Tags | Agentic Free API tier Long context Reasoning Tool use |
| End of life | Not disclosed |
| Last verified | Not disclosed |