Moonshot AI Kimi Linear vs xAI Grok 4 Fast — side-by-side specs.
Moonshot AI Kimi Linear | xAI Grok 4 Fast | |
|---|---|---|
| Overview | ||
| Company | Moonshot AI | xAI |
| Release date | Oct 2025 | Sep 2025 |
| Model type | — | — |
| Open source | Yes | No |
| Specifications | ||
Parameters | 48B | — |
Context window | — | — |
| Benchmarks | ||
| Timeline | ||
| Release gap | Grok 4 Fast shipped 30 days before Kimi Linear | |
Kimi Linear and Grok 4 Fast don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Grok 4 Fast shipped 30 days before Kimi Linear, so benchmark comparisons should account for the intervening progress.
Kimi Linear is an open-source / open-weight model; Grok 4 Fast is proprietary.
Direct benchmark comparisons are unavailable — Kimi Linear and Grok 4 Fast don't publish scores on any of the same benchmarks.