Mistral AI unveils Medium 3.5, a 128B-parameter open-source breakthrough

A leap forward in AI flexibility: Mistral's latest model merges three predecessors into one adaptable system. Will it redefine enterprise AI standards?

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2026 May 1 . 5:02 PM

1 min read

The image shows a colorful design on the right side with the words "AI, Apps, IoT" written on it... — The image shows a colorful design on the right side with the words "AI, Apps, IoT" written on it against a white background.

Mistral AI unveils Medium 3.5, a 128B-parameter open-source breakthrough

Mistral AI has launched its latest model, Mistral Medium 3.5, marking a significant step in open-source artificial intelligence. Released on 29 April 2023, the 128-billion-parameter system stands out as one of the few non-Chinese models making waves in the field. The company’s European base and focus on legal compliance for businesses add to its growing appeal. The new model merges three previous versions into a single, flexible system. Users can now adjust reasoning effort per request, tailoring performance to specific needs. Pricing is set at $1.50 per million input tokens and $7.50 per million output tokens.

Benchmarks show strong results, with Mistral Medium 3.5 scoring 77.6% on SWE-Bench Verified and 91.4% on â4â3-Telecom. However, it has yet to appear on major independent leaderboards. Competitors like Alibaba’s Qwen 3.6, which has fewer parameters, deliver similar performance but remain free to use.

Alongside the model, Mistral introduced new tools for developers. These include remote coding agents via the Mistral Vibe CLI and a Work Mode feature in Le Chat. The updates aim to streamline workflows for technical users. Mistral Medium 3.5 reinforces the company’s position as a key player in European AI development. Its configurable reasoning and strong benchmark scores provide options for enterprise users. Meanwhile, the model’s pricing and tooling expansions reflect Mistral’s push to balance performance with accessibility.