Moonshot AI Kimi K1.5 vs OpenAI GPT-5.3-Codex — side-by-side specs.
Moonshot AI Kimi K1.5 | OpenAI GPT-5.3-Codex | |
|---|---|---|
| Overview | ||
| Company | Moonshot AI | OpenAI |
| Release date | Jan 20 2025 | Feb 5 2026 |
| Model type | — | — |
| Open source | No | No |
| Specifications | ||
Parameters | — | — |
Context window | 128k | — |
| Benchmarks | ||
| Timeline | ||
| Release gap | Kimi K1.5 shipped 381 days before GPT-5.3-Codex | |
Kimi K1.5 and GPT-5.3-Codex don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Kimi K1.5 shipped 381 days before GPT-5.3-Codex, 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 GPT-5.3-Codex don't publish scores on any of the same benchmarks.