Grok 4.1 Fast Reasoning
Grok 4.1 Fast Reasoning is SpaceXAI's reasoning-enabled Grok 4.1 Fast model optimized for agentic operations. It combines structured chain-of-thought reasoning with speed-optimized inference and a context window of 1M tokens for complex agent workflows. Your use is subject to SpaceXAI's Terms & Privacy Policies.
ReasoningFile InputVision (Image)Tool UseImplicit Caching
import { streamText } from 'ai'
const result = streamText({ model: 'spacexai/grok-4.1-fast-reasoning', prompt: 'Why is the sky blue?'})Copy link to headingMore models by SpaceXAI
| Model |
|---|
| 500K | $2/M+1 more | $6/M+1 more | Read: $0.50/M+1 more Write: — | $5/K + input costs | +1 |  | 08/12/2026 | |||||||
| 500K | $2/M+1 more | $6/M+1 more | Read: $0.30/M+1 more Write: — | $5/K + input costs | +3 | | 07/08/2026 | |||||||
| 1M | $1.25/M+1 more | $2.50/M+1 more | Read: $0.20/M+1 more Write: — | $5/K + input costs | +3 |  | 04/30/2026 | |||||||
| 2M | $1.25/M+1 more | $2.50/M+1 more | Read: $0.20/M+1 more Write: — | $5/K + input costs | +2 | | 03/10/2026 | |||||||
| 2M | $1.25/M+1 more | $2.50/M+1 more | Read: $0.20/M+1 more Write: — | $5/K + input costs | +3 | | 03/10/2026 | |||||||
| 1M | $0.20/M | $0.50/M | Read:$0.05/M Write:— | — | +1 | | 11/19/2025 |