DeepSeek DeepSeek-V4-Flash vs OpenAI GPT-5.3-Codex — side-by-side specs.
DeepSeek DeepSeek-V4-Flash | OpenAI GPT-5.3-Codex | |
|---|---|---|
| Overview | ||
| Company | DeepSeek | OpenAI |
| Release date | Apr 24 2026 | Feb 5 2026 |
| Model type | — | — |
| Open source | Yes | No |
| Specifications | ||
Parameters | — | — |
Context window | — | — |
| Benchmarks | ||
Science GPQA DiamondGraduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 88.1% | — |
| Timeline | ||
| Release gap | GPT-5.3-Codex shipped 78 days before DeepSeek-V4-Flash | |
DeepSeek-V4-Flash and GPT-5.3-Codex don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. GPT-5.3-Codex shipped 78 days before DeepSeek-V4-Flash, so benchmark comparisons should account for the intervening progress.
DeepSeek-V4-Flash is an open-source / open-weight model; GPT-5.3-Codex is proprietary.
Direct benchmark comparisons are unavailable — DeepSeek-V4-Flash and GPT-5.3-Codex don't publish scores on any of the same benchmarks.