Mistral Medium 3.5 Is Now Available in Puter.js

Puter.js now supports Mistral Medium 3.5, the new flagship merged model from Mistral AI that unifies instruction-following, reasoning, and agentic coding into a single set of weights. Add it to your application for free without any API keys.

What is Mistral Medium 3.5?

Mistral Medium 3.5 is a dense 128B-parameter multimodal model with a 256K context window, replacing Mistral's previous Medium 3.1, Magistral, and Devstral 2 models in one consolidated release. It features native function calling, structured JSON output, and vision capabilities via a custom-trained encoder that handles variable image sizes. A per-request reasoning_effort parameter lets you toggle between fast responses and deeper chain-of-thought processing, making the same model suitable for quick chat replies and long-horizon agentic workflows. It scores 77.6% on SWE-Bench Verified and 91.4% on τ³-Telecom.

Examples

Basic Chat

puter.ai.chat("Explain the concept of quantum computing in simple terms",
    { model: "mistralai/mistral-medium-3-5" }
)

Image Analysis

puter.ai.chat("What do you see in this image?",
    "https://assets.puter.site/doge.jpeg",
    { model: "mistralai/mistral-medium-3-5" }
)

Agentic Coding

puter.ai.chat(
    "Create a simple to-do list app in a single HTML file with add, delete, and mark complete features",
    { model: "mistralai/mistral-medium-3-5" }
)

Get Started Now

Just add one library to your project:

// npm install @heyputer/puter.js
import { puter } from '@heyputer/puter.js';

Or add one script tag to your HTML:

<script src="https://js.puter.com/v2/"></script>

No API keys or infrastructure setup needed. Start building with Mistral Medium 3.5 immediately.

Learn more:

• Free, Unlimited Mistral API
• Puter.js AI Documentation