Devstral Small vs GPT-5.5-Pro
Mistral Devstral Small | OpenAI GPT-5.5-Pro | |
|---|---|---|
| Overview | ||
| Company | Mistral | OpenAI |
| Release date | May 21 2025 | Apr 23 2026 |
| Access | Open Weight | Proprietary |
| Specifications | ||
Parameters | 24B | — |
| 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. | — | 36% |
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% |
Web browsing BrowseCompCan the AI browse the web and track down hard-to-find answers? Higher is better. | — | 90.1% |
Multidisciplinary reasoning Humanity's Last Exam · with toolsHumanity's Last Exam — extremely hard expert questions across many subjects. “With tools” means the AI is allowed to search the web or run code while answering. Higher is better. | — | 57.2% |
Advanced math FrontierMath · Tier 1–3Very hard, research-level math problems. Tiers 1–3 are the (still extremely difficult) lower tiers. Higher is better. | — | 52.4% |
Advanced math FrontierMath · Tier 4Very hard, research-level math problems. Tier 4 is the hardest — close to what professional research mathematicians tackle. Higher is better. | — | 39.6% |
Knowledge work GDPval (win/tie rate)How often the AI's work matches or beats a human expert's on real knowledge-work tasks. Higher is better. | — | 82.3% |
| Timeline | ||
| Release gap | Devstral Small shipped 337 days before GPT-5.5-Pro | |
Which is better: Devstral Small or GPT-5.5-Pro?
Devstral Small and GPT-5.5-Pro don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Devstral Small shipped 337 days before GPT-5.5-Pro, so benchmark comparisons should account for the intervening progress.
Devstral Small is open weight, while GPT-5.5-Pro is proprietary.
Direct benchmark comparisons are unavailable — Devstral Small and GPT-5.5-Pro don't publish scores on any of the same benchmarks.
Frequently asked questions
Devstral Small was released by Mistral on May 21 2025.
GPT-5.5-Pro was released by OpenAI on Apr 23 2026.
Devstral Small is an open weight model released by Mistral. GPT-5.5-Pro is a proprietary model released by OpenAI.
Other comparisons
Devstral Small vs Claude Sonnet 5GPT-5.5-Pro vs Claude Sonnet 5Devstral Small vs Gemini OmniGPT-5.5-Pro vs Gemini OmniDevstral Small vs Muse Spark 1.1GPT-5.5-Pro vs Muse Spark 1.1Devstral Small vs Grok 4.5GPT-5.5-Pro vs Grok 4.5Devstral Small vs DeepSeek-V4-ProGPT-5.5-Pro vs DeepSeek-V4-ProDevstral Small vs Kimi K2.7 CodeGPT-5.5-Pro vs Kimi K2.7 Code