DeepSeek-V4-FlashvsGPT-5.3-Codex
DeepSeek-V4-Flash | GPT-5.3-Codex | |
|---|---|---|
| Benchmarks | ||
Nonsense detection BullshitBench v2Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better. | 18% | 24%Best |
Next.js coding Next.js EvalsVercel's open eval of how well AI coding agents build and migrate real Next.js apps — measured as the share of tasks the agent completes successfully. Higher is better. | — | 83% |
Competitive coding LiveCodeBenchCoding problems published so recently the AI can't have seen them in training — a contamination-free test of raw programming skill. Higher is better. | 91.6% | — |
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% | — |
Community preference (code) Arena Elo (Code)Like the text arena, but people vote on which AI writes better code. The votes become a chess-style Elo rating on arena.ai. Higher is better. | — | 1406 |
| Timeline | ||
| Release gap | GPT-5.3-Codex shipped 78 days before DeepSeek-V4-Flash | |
| Overview | ||
| Company | DeepSeek | OpenAI |
| Release date | Apr 24 2026 | Feb 5 2026 |
| Access | Open Weight | Proprietary |
Which is better: DeepSeek-V4-Flash or GPT-5.3-Codex?
GPT-5.3-Codex leads DeepSeek-V4-Flash on 1 of the 1 benchmark they both report (BullshitBench v2). GPT-5.3-Codex shipped 78 days before DeepSeek-V4-Flash, so benchmark comparisons should account for the intervening progress.
DeepSeek-V4-Flash is open weight, while GPT-5.3-Codex is proprietary.
On BullshitBench v2, GPT-5.3-Codex leads at 24% vs DeepSeek-V4-Flash at 18%.
Frequently asked questions
DeepSeek-V4-Flash was released by DeepSeek on Apr 24 2026.
GPT-5.3-Codex was released by OpenAI on Feb 5 2026.
DeepSeek-V4-Flash is an open weight model released by DeepSeek. GPT-5.3-Codex is a proprietary model released by OpenAI.
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