Moonshot AI Kimi Linear vs OpenAI GPT-5.3-Codex-Spark — side-by-side specs.
Moonshot AI Kimi Linear | OpenAI GPT-5.3-Codex-Spark | |
|---|---|---|
| Overview | ||
| Company | Moonshot AI | OpenAI |
| Release date | Oct 2025 | Feb 12 2026 |
| Model type | — | — |
| Open source | Yes | No |
| Specifications | ||
Parameters | 48B | — |
Context window | — | 128k |
| Benchmarks | ||
Science reasoning GPQA Diamond | — | — |
Software engineering SWE-Bench Verified | — | — |
Multimodal understanding MMMU | — | — |
| Timeline | ||
| Release gap | Kimi Linear shipped 134 days before GPT-5.3-Codex-Spark | |
Kimi Linear and GPT-5.3-Codex-Spark do not have directly comparable benchmark scores published on GPQA Diamond, SWE-Bench Verified, or MMMU. Kimi Linear shipped 134 days before GPT-5.3-Codex-Spark, so benchmark comparisons should account for the intervening progress.
Kimi Linear is an open-source / open-weight model; GPT-5.3-Codex-Spark is proprietary.
Direct benchmark comparisons are unavailable — at least one of these models has not published scores on GPQA Diamond, SWE-Bench Verified, or MMMU.