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OpenKey

Mistral Small 4

Mistral AIReleased Mar 16, 2026

Mistral Small 4 is the next major release in the Mistral Small family, unifying the capabilities of several flagship Mistral models into a single system. It combines strong reasoning from...

Try in playground
Context window
262K tokens
Input
text, image
Output
text
Tokenizer
Mistral
Released
Mar 16, 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$0.150$0.0045$0.154
Output$0.600$0.018$0.618
Cache read$0.015$0.0004$0.015

Supported parameters

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

Call it

OpenAI-compatible: point your SDK at api.openkey.ai/v1 and use model mistralai/mistral-small-2603.

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-small-2603",
    "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-small-2603",
    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-small-2603",
  messages: [{ role: "user", content: "Hello" }],
});
console.log(completion.choices[0].message.content);

Questions

How much does Mistral Small 4 cost via API?
Through OpenKey, Mistral Small 4 costs $0.154 per 1M input tokens and $0.618 per 1M output tokens. That is the provider price ($0.150 / $0.600) plus a flat 3% fee — nothing else.
What is Mistral Small 4's context window?
Mistral Small 4 accepts up to 262K tokens of context.
Is Mistral Small 4 OpenAI-compatible?
Yes. Send requests to OpenKey's /v1/chat/completions endpoint with model "mistralai/mistral-small-2603" using any OpenAI SDK — only the base URL and API key change.
What inputs does Mistral Small 4 support?
Mistral Small 4 accepts text, image input and produces text output.

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