grok-4-1-fast-reasoning
Summary
grok-4-1-fast-reasoning is a proprietary language model from xAI, released on 20 Nov 2025. It accepts text and images and generates text, with a 2M-token context window and up to 30K output tokens per response. As of 4 Oct 2026, the lowest listed API price is $0.20 per million input tokens and $0.50 per million output tokens (Azure AI Foundry), across 2 providers we track.
Fast Grok model for responsive chat, reasoning, and tool-assisted work
Last verified 4 Oct 2026. Every figure on this page links to its source.
Specifications
| Developer | xAI |
|---|---|
| Release date | 20 Nov 2025 [models.dev] |
| Status | Generally available [models.dev] |
| Weights | Proprietary (API only) [models.dev] |
| Context window | 2M (2,000,000 tokens) [models.dev] |
| Max output | 30K tokens [models.dev] |
| Knowledge cutoff | Jun 2025 [models.dev] |
| Input | Text and images [models.dev] |
| Output | Text [models.dev] |
| Reasoning mode | Yes [models.dev] |
| Tool calling | Yes [models.dev] |
grok-4-1-fast-reasoning API pricing by provider
USD per million tokens. Sorted by input price.
| Provider | Input | Output | Cached input | Context | Source |
|---|---|---|---|---|---|
| Azure AI Foundry grok-4-1-fast-reasoning | $0.20 | $0.50 | $0.05 | 128K | models.dev, 4 Oct 2026 |
| Vercel AI Gateway spacexai/grok-4.1-fast-reasoning | $0.20 | $0.50 | $0.05 | 1M | models.dev, 4 Oct 2026 |
Frequently asked questions
What is the context window of grok-4-1-fast-reasoning?
grok-4-1-fast-reasoning has a context window of 2,000,000 tokens (2M) and can generate up to 30,000 tokens in a single response, according to models.dev.
How much does the grok-4-1-fast-reasoning API cost?
grok-4-1-fast-reasoning is listed from $0.20 per million input tokens and $0.50 per million output tokens (Azure AI Foundry). Prices last verified 4 Oct 2026.
Is grok-4-1-fast-reasoning open source?
No. grok-4-1-fast-reasoning is a proprietary model; xAI has not released its weights. It is available through APIs including Azure AI Foundry, Vercel AI Gateway.
When was grok-4-1-fast-reasoning released?
xAI released grok-4-1-fast-reasoning on 20 Nov 2025, according to models.dev.
Which providers offer grok-4-1-fast-reasoning?
We track grok-4-1-fast-reasoning on 2 providers: Azure AI Foundry, Vercel AI Gateway.
Change history
No changes detected since we started tracking this model. We re-check every source daily.