AI Model Release Tracker - Timeline of Major AI Models from 2022-2026

Mistral Medium 3.5 vs o1-pro

Mistral
Mistral Medium 3.5
OpenAI
o1-pro
Overview
CompanyMistralOpenAI
Release dateApr 29 2026Mar 19 2025
Model type
Open sourceYesNo
Specifications
Parameters
128B
Context window
256k
Benchmarks
Coding
SWE-Bench Verified
77.6%
Timeline
Release gapo1-pro shipped 406 days before Mistral Medium 3.5

Which is better: Mistral Medium 3.5 or o1-pro?

Mistral Medium 3.5 and o1-pro don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. o1-pro shipped 406 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; o1-pro is proprietary.

Direct benchmark comparisons are unavailable — Mistral Medium 3.5 and o1-pro don't publish scores on any of the same benchmarks.

Frequently asked questions

When was Mistral Medium 3.5 released?
Mistral Medium 3.5 was released by Mistral on Apr 29 2026.
When was o1-pro released?
o1-pro was released by OpenAI on Mar 19 2025.
Is Mistral Medium 3.5 or o1-pro open source?
Mistral Medium 3.5 is an open-source / open-weight model released by Mistral. o1-pro is a proprietary model released by OpenAI.

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