When was Mistral Medium 3.5 released?

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

When was GPT-5.3-Codex-Spark released?

GPT-5.3-Codex-Spark was released by OpenAI on Feb 12 2026.

How do the context windows of Mistral Medium 3.5 and GPT-5.3-Codex-Spark compare?

Mistral Medium 3.5 has a 256k context window; GPT-5.3-Codex-Spark has 128k.

Is Mistral Medium 3.5 or GPT-5.3-Codex-Spark open source?

Mistral Medium 3.5 is an open-source / open-weight model released by Mistral. GPT-5.3-Codex-Spark is a proprietary model released by OpenAI.

Home Analytics Contact

Latest Release

Mistral Medium 3.5

Apr 29 2026

Home/Compare/Mistral Medium 3.5 vs GPT-5.3-Codex-Spark

Mistral Medium 3.5 vs GPT-5.3-Codex-Spark

1 vs 0 benchmarks won

	Mistral Mistral Medium 3.5	OpenAI GPT-5.3-Codex-Spark
Overview
Company	Mistral	OpenAI
Release date	Apr 29 2026	Feb 12 2026
Model type	—	—
Open source	Yes	No
Specifications
Parameters	128B	—
Context window	256k	128k
Benchmarks
Science reasoning GPQA Diamond	—	—
Software engineering SWE-Bench Verified	77.6%	—
Multimodal understanding MMMU	—	—
Timeline
Release gap	GPT-5.3-Codex-Spark shipped 76 days before Mistral Medium 3.5

Which is better: Mistral Medium 3.5 or GPT-5.3-Codex-Spark?

Mistral Medium 3.5 leads GPT-5.3-Codex-Spark on 1 of the tracked benchmarks (GPQA Diamond, SWE-Bench Verified, MMMU). GPT-5.3-Codex-Spark shipped 76 days before Mistral Medium 3.5, so benchmark comparisons should account for the intervening progress.

Context windows are 256k (Mistral Medium 3.5) vs 128k (GPT-5.3-Codex-Spark). Mistral Medium 3.5 is an open-source / open-weight model; GPT-5.3-Codex-Spark is proprietary.

Direct benchmark comparisons are unavailable — at least one of these models has not published scores on GPQA Diamond, SWE-Bench Verified, or MMMU.

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-5.3-Codex-Spark released?: GPT-5.3-Codex-Spark was released by OpenAI on Feb 12 2026.
How do the context windows of Mistral Medium 3.5 and GPT-5.3-Codex-Spark compare?: Mistral Medium 3.5 has a 256k context window; GPT-5.3-Codex-Spark has 128k.
Is Mistral Medium 3.5 or GPT-5.3-Codex-Spark open source?: Mistral Medium 3.5 is an open-source / open-weight model released by Mistral. GPT-5.3-Codex-Spark is a proprietary model released by OpenAI.