When was Mistral Medium 3.5 released?

Mistral Medium 3.5 was released by Mistral on Apr 29 2026.

When was GPT-5.1 released?

GPT-5.1 was released by OpenAI on Nov 12 2025.

Which is better at coding, Mistral Medium 3.5 or GPT-5.1?

On SWE-Bench Verified (real-world software-engineering tasks), Mistral Medium 3.5 leads — Mistral Medium 3.5 scores 77.6% and GPT-5.1 scores 76.3%.

Is Mistral Medium 3.5 or GPT-5.1 open source?

Mistral Medium 3.5 is an open-source / open-weight model released by Mistral. GPT-5.1 is a proprietary model released by OpenAI.

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Mistral Medium 3.5

Apr 29 2026

Home/Compare/Mistral Medium 3.5 vs GPT-5.1

Mistral Medium 3.5 vs GPT-5.1

1 vs 2 benchmarks won

	Mistral Mistral Medium 3.5	OpenAI GPT-5.1
Overview
Company	Mistral	OpenAI
Release date	Apr 29 2026	Nov 12 2025
Model type	—	—
Open source	Yes	No
Specifications
Parameters	128B	—
Context window	256k	—
Benchmarks
Science reasoning GPQA Diamond	—	88.1%
Software engineering SWE-Bench Verified	77.6%	76.3%
Multimodal understanding MMMU	—	76%
Timeline
Release gap	GPT-5.1 shipped 168 days before Mistral Medium 3.5

Which is better: Mistral Medium 3.5 or GPT-5.1?

GPT-5.1 leads Mistral Medium 3.5 on 2 of the tracked benchmarks (GPQA Diamond, SWE-Bench Verified, MMMU). GPT-5.1 shipped 168 days before Mistral Medium 3.5, so benchmark comparisons should account for the intervening progress.

Mistral Medium 3.5 is an open-source / open-weight model; GPT-5.1 is proprietary.

On SWE-Bench Verified, Mistral Medium 3.5 scores 77.6%, 1.3 points above GPT-5.1 at 76.3%.

Frequently asked questions

When was Mistral Medium 3.5 released?: Mistral Medium 3.5 was released by Mistral on Apr 29 2026.
When was GPT-5.1 released?: GPT-5.1 was released by OpenAI on Nov 12 2025.
Which is better at coding, Mistral Medium 3.5 or GPT-5.1?: On SWE-Bench Verified (real-world software-engineering tasks), Mistral Medium 3.5 leads — Mistral Medium 3.5 scores 77.6% and GPT-5.1 scores 76.3%.
Is Mistral Medium 3.5 or GPT-5.1 open source?: Mistral Medium 3.5 is an open-source / open-weight model released by Mistral. GPT-5.1 is a proprietary model released by OpenAI.