Moonshot AI Kimi K1.5 vs xAI Grok 4 Fast — side-by-side specs.
Moonshot AI Kimi K1.5 | xAI Grok 4 Fast | |
|---|---|---|
| Overview | ||
| Company | Moonshot AI | xAI |
| Release date | Jan 20 2025 | Sep 2025 |
| Model type | — | — |
| Open source | No | No |
| Specifications | ||
Parameters | — | — |
Context window | 128k | — |
| Benchmarks | ||
| Timeline | ||
| Release gap | Kimi K1.5 shipped 224 days before Grok 4 Fast | |
Kimi K1.5 and Grok 4 Fast don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Kimi K1.5 shipped 224 days before Grok 4 Fast, so benchmark comparisons should account for the intervening progress.
Published specifications for these two models are limited — see each model page for the latest details.
Direct benchmark comparisons are unavailable — Kimi K1.5 and Grok 4 Fast don't publish scores on any of the same benchmarks.