Devstral 2 (123B) vs GPT-5.3-Codex
Mistral Devstral 2 (123B) | OpenAI GPT-5.3-Codex | |
|---|---|---|
| Overview | ||
| Company | Mistral | OpenAI |
| Release date | Dec 9 2025 | Feb 5 2026 |
| Access | Open Weight | Proprietary |
| 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. | — | 24% |
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% |
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 | Devstral 2 (123B) shipped 58 days before GPT-5.3-Codex | |
Which is better: Devstral 2 (123B) or GPT-5.3-Codex?
Devstral 2 (123B) and GPT-5.3-Codex don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Devstral 2 (123B) shipped 58 days before GPT-5.3-Codex, so benchmark comparisons should account for the intervening progress.
Devstral 2 (123B) is open weight, while GPT-5.3-Codex is proprietary.
Direct benchmark comparisons are unavailable — Devstral 2 (123B) and GPT-5.3-Codex don't publish scores on any of the same benchmarks.
Frequently asked questions
Devstral 2 (123B) was released by Mistral on Dec 9 2025.
GPT-5.3-Codex was released by OpenAI on Feb 5 2026.
Devstral 2 (123B) is an open weight model released by Mistral. GPT-5.3-Codex is a proprietary model released by OpenAI.
Other comparisons
Devstral 2 (123B) vs Claude Sonnet 5GPT-5.3-Codex vs Claude Sonnet 5Devstral 2 (123B) vs Gemini 3.5 FlashGPT-5.3-Codex vs Gemini 3.5 FlashDevstral 2 (123B) vs Muse Spark 1.1GPT-5.3-Codex vs Muse Spark 1.1Devstral 2 (123B) vs Grok 4.5GPT-5.3-Codex vs Grok 4.5Devstral 2 (123B) vs DeepSeek-V4-ProGPT-5.3-Codex vs DeepSeek-V4-ProDevstral 2 (123B) vs Kimi K2.7 CodeGPT-5.3-Codex vs Kimi K2.7 Code