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

Mistral Medium 3.5 vs o3-mini

Mistral
Mistral Medium 3.5
OpenAI
o3-mini
Overview
CompanyMistralOpenAI
Release dateApr 29 2026Jan 31 2025
Model type
Open sourceYesNo
Specifications
Parameters
128B
Context window
256k
Benchmarks
Coding
SWE-Bench Verified
77.6%
Timeline
Release gapo3-mini shipped 453 days before Mistral Medium 3.5

Which is better: Mistral Medium 3.5 or o3-mini?

Mistral Medium 3.5 and o3-mini don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. o3-mini shipped 453 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; o3-mini is proprietary.

Direct benchmark comparisons are unavailable — Mistral Medium 3.5 and o3-mini 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 o3-mini released?
o3-mini was released by OpenAI on Jan 31 2025.
Is Mistral Medium 3.5 or o3-mini open source?
Mistral Medium 3.5 is an open-source / open-weight model released by Mistral. o3-mini is a proprietary model released by OpenAI.

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