Moonshot AI Kimi Linear vs OpenAI GPT-5.3-Codex — side-by-side specs.
Moonshot AI Kimi Linear | OpenAI GPT-5.3-Codex | |
|---|---|---|
| Overview | ||
| Company | Moonshot AI | OpenAI |
| Release date | Oct 2025 | Feb 5 2026 |
| Model type | — | — |
| Open source | Yes | No |
| Specifications | ||
Parameters | 48B | — |
Context window | — | — |
| Benchmarks | ||
| Timeline | ||
| Release gap | Kimi Linear shipped 127 days before GPT-5.3-Codex | |
Kimi Linear 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 Linear shipped 127 days before GPT-5.3-Codex, so benchmark comparisons should account for the intervening progress.
Kimi Linear is an open-source / open-weight model; GPT-5.3-Codex is proprietary.
Direct benchmark comparisons are unavailable — Kimi Linear and GPT-5.3-Codex don't publish scores on any of the same benchmarks.