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

Mistral Medium 3.5 vs Grok 4.20 Beta

Mistral
Mistral Medium 3.5
SpaceXAI
Grok 4.20 Beta
Overview
CompanyMistralSpaceXAI
Release dateApr 29 2026Feb 17 2026
AccessOpen WeightProprietary
Specifications
Parameters
128B
Context window
256k
Benchmarks
Nonsense detection
BullshitBench v2
56%
Coding
SWE-Bench Verified
77.6%
Timeline
Release gapGrok 4.20 Beta shipped 71 days before Mistral Medium 3.5

Which is better: Mistral Medium 3.5 or Grok 4.20 Beta?

Mistral Medium 3.5 and Grok 4.20 Beta don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Grok 4.20 Beta shipped 71 days before Mistral Medium 3.5, so benchmark comparisons should account for the intervening progress.

Mistral Medium 3.5 is open weight, while Grok 4.20 Beta is proprietary.

Direct benchmark comparisons are unavailable — Mistral Medium 3.5 and Grok 4.20 Beta don't publish scores on any of the same benchmarks.

Frequently asked questions

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

Grok 4.20 Beta was released by SpaceXAI on Feb 17 2026.

Mistral Medium 3.5 is an open weight model released by Mistral. Grok 4.20 Beta is a proprietary model released by SpaceXAI.

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