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Mistral Medium 3.5

Mistral AIReleased Apr 30, 2026

Mistral Medium 3.5 is a dense 128B instruction-following model from Mistral AI. It supports text and image inputs with text output, and is designed for agentic workflows, coding, and complex...

Try in playground
Context window
262K tokens
Input
text, image, file
Output
text
Tokenizer
Mistral
Released
Apr 30, 2026
Reasoning
optional

Pricing

Per 1M tokens. The provider price and our flat 3% fee are separate columns — what you pay is their sum.

Per 1M tokensProvider+ 3% feeYou pay
Input$1.50$0.045$1.54
Output$7.50$0.225$7.73

Benchmarks

Artificial Analysis

Intelligence index
29.9
Coding index
46.9
Agentic index
19

Supported parameters

  • frequency_penalty
  • include_reasoning
  • max_tokens
  • presence_penalty
  • reasoning
  • response_format
  • seed
  • stop
  • structured_outputs
  • temperature
  • tool_choice
  • tools
  • top_p

Call it

OpenAI-compatible: point your SDK at api.openkey.ai/v1 and use model mistralai/mistral-medium-3-5.

Code sample language
curl https://api.openkey.ai/v1/chat/completions \
  -H "Authorization: Bearer $OPENKEY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "mistralai/mistral-medium-3-5",
    "messages": [{"role": "user", "content": "Hello"}]
  }'
import os
from openai import OpenAI

client = OpenAI(
    base_url="https://api.openkey.ai/v1",
    api_key=os.environ["OPENKEY_API_KEY"],
)

completion = client.chat.completions.create(
    model="mistralai/mistral-medium-3-5",
    messages=[{"role": "user", "content": "Hello"}],
)
print(completion.choices[0].message.content)
import OpenAI from "openai";

const client = new OpenAI({
  baseURL: "https://api.openkey.ai/v1",
  apiKey: process.env.OPENKEY_API_KEY,
});

const completion = await client.chat.completions.create({
  model: "mistralai/mistral-medium-3-5",
  messages: [{ role: "user", content: "Hello" }],
});
console.log(completion.choices[0].message.content);

Questions

How much does Mistral Medium 3.5 cost via API?
Through OpenKey, Mistral Medium 3.5 costs $1.54 per 1M input tokens and $7.73 per 1M output tokens. That is the provider price ($1.50 / $7.50) plus a flat 3% fee — nothing else.
What is Mistral Medium 3.5's context window?
Mistral Medium 3.5 accepts up to 262K tokens of context.
Is Mistral Medium 3.5 OpenAI-compatible?
Yes. Send requests to OpenKey's /v1/chat/completions endpoint with model "mistralai/mistral-medium-3-5" using any OpenAI SDK — only the base URL and API key change.
What inputs does Mistral Medium 3.5 support?
Mistral Medium 3.5 accepts text, image, file input and produces text output.

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