Mistral Medium 3.1

Mistral Medium 3.1 – Frontier-Class Multimodal Enterprise Model

Mistral Medium 3.1 (mistral-medium-2508) is Mistral AI's frontier-class multimodal model released in August 2025, officially described as improving tone and performance over its predecessor. It is classified as a Premier tier model — a commercial-only offering within Mistral's lineup — and has since been superseded by Mistral Medium 3.5.

Feature Set

Officially documented API capabilities include: Chat Completions, Function Calling, Agents & Conversations, Built-In Tools, Structured Outputs, Predicted Outputs, Prefix, OCR (with Annotations and BBox Extraction), Document QnA, FIM (Fill-in-the-Middle), Embeddings, Moderations, Chat Moderations, Transcriptions, Text to Speech, Timestamps, and Batching.

Deployment & Enterprise Design

Mistral AI documents Mistral Medium 3.1 as supporting hybrid, on-premises, and in-VPC deployment, as well as continuous pretraining, full fine-tuning, and integration into enterprise knowledge bases — enabling domain-specific adaptation without starting from scratch.

Why It Exists

Mistral Medium 3.1 was positioned as a frontier-quality model delivering enterprise adaptation capabilities and multimodal understanding at a significantly lower cost than comparable large models, continuing the Medium family's design goal of balancing performance and deployability.