Overview
Mistral AI is a French AI company providing high-quality, cost-efficient language models with EU data residency and GDPR compliance. Their models excel at code generation (Codestral), multilingual tasks, and reasoning. Mistral's API follows OpenAI conventions closely, making integration straightforward.
Setup
bash
# Python
pip install mistralai
# TypeScript/Node
npm install @mistralai/mistralai
bash
export MISTRAL_API_KEY=...
Available Models
| Model | Context | Best For |
|---|---|---|
mistral-large-latest | 128k | Most capable, complex reasoning |
mistral-small-latest | 128k | Cost-efficient, everyday tasks |
codestral-latest | 256k | Code generation & completion |
mistral-embed | 8k | Text embeddings |
open-mistral-nemo | 128k | Open-weight, edge deployment |
Instructions
Basic Chat Completion (Python)
python
from mistralai import Mistral
client = Mistral(api_key="your_api_key") # or reads MISTRAL_API_KEY
response = client.chat.complete(
model="mistral-large-latest",
messages=[
{"role": "system", "content": "You are a helpful assistant."},
{"role": "user", "content": "Explain the difference between async and sync programming."},
],
)
print(response.choices[0].message.content)
print(f"Prompt tokens: {response.usage.prompt_tokens}")
print(f"Completion tokens: {response.usage.completion_tokens}")
TypeScript/Node.js
typescript
import Mistral from "@mistralai/mistralai";
const client = new Mistral({ apiKey: process.env.MISTRAL_API_KEY });
const response = await client.chat.complete({
model: "mistral-large-latest",
messages: [{ role: "user", content: "Hello from TypeScript!" }],
});
console.log(response.choices[0].message.content);
Streaming
python
from mistralai import Mistral
client = Mistral()
stream = client.chat.stream(
model="mistral-small-latest",
messages=[{"role": "user", "content": "Write a haiku about programming."}],
)
for event in stream:
chunk = event.data.choices[0].delta.content
if chunk:
print(chunk, end="", flush=True)
print()
Function Calling
python
import json
from mistralai import Mistral
client = Mistral()
tools = [
{
"type": "function",
"function": {
"name": "search_products",
"description": "Search for products in a catalog",
"parameters": {
"type": "object",
"properties": {
"query": {"type": "string"},
"max_price": {"type": "number"},
"category": {"type": "string"},
},
"required": ["query"],
},
},
}
]
messages = [{"role": "user", "content": "Find laptops under $1000"}]
response = client.chat.complete(
model="mistral-large-latest",
messages=messages,
tools=tools,
tool_choice="auto",
)
if response.choices[0].finish_reason == "tool_calls":
tool_call = response.choices[0].message.tool_calls[0]
args = json.loads(tool_call.function.arguments)
print(f"Function: {tool_call.function.name}, Args: {args}")
# Add tool result and continue
messages.append(response.choices[0].message)
messages.append({
"role": "tool",
"tool_call_id": tool_call.id,
"content": json.dumps([{"name": "ThinkPad X1", "price": 899}]),
})
final = client.chat.complete(model="mistral-large-latest", messages=messages)
print(final.choices[0].message.content)
JSON Mode
python
from mistralai import Mistral
import json
client = Mistral()
response = client.chat.complete(
model="mistral-small-latest",
messages=[
{
"role": "user",
"content": "Return a JSON object with fields: title, author, year for the book '1984'",
}
],
response_format={"type": "json_object"},
)
data = json.loads(response.choices[0].message.content)
print(data) # {"title": "1984", "author": "George Orwell", "year": 1949}
Text Embeddings
python
from mistralai import Mistral
client = Mistral()
response = client.embeddings.create(
model="mistral-embed",
inputs=["Machine learning is transforming industries.", "AI is the future of technology."],
)
embeddings = [item.embedding for item in response.data]
print(f"Embedding dimension: {len(embeddings[0])}") # 1024
# Compute cosine similarity
import numpy as np
def cosine_similarity(a, b):
return np.dot(a, b) / (np.linalg.norm(a) * np.linalg.norm(b))
similarity = cosine_similarity(embeddings[0], embeddings[1])
print(f"Similarity: {similarity:.3f}")
Codestral for Code Completion
python
from mistralai import Mistral
client = Mistral()
# Fill-in-the-middle (FIM) — Codestral's signature feature
response = client.fim.complete(
model="codestral-latest",
prompt="def fibonacci(n):\n if n <= 1:\n return n\n ",
suffix="\n\nresult = fibonacci(10)\nprint(result)",
)
print(response.choices[0].message.content)
# Returns the middle code that connects prompt to suffix
python
# Standard code generation
response = client.chat.complete(
model="codestral-latest",
messages=[
{
"role": "user",
"content": "Write a Python class for a rate limiter using token bucket algorithm.",
}
],
)
print(response.choices[0].message.content)
GDPR Compliance Notes
- All API data processed in EU data centers by default.
- Mistral AI is headquartered in Paris, France — subject to EU/GDPR jurisdiction.
- For enterprise data residency guarantees, use Mistral's Azure or GCP deployments.
- No training on user data by default — check your plan's DPA for details.
Guidelines
- Use
mistral-large-latestfor complex tasks,mistral-small-latestfor cost savings. - Codestral is specialized for code and significantly outperforms general models on FIM tasks.
- The
mistral-embedmodel produces 1024-dimensional vectors. - Mistral models have strong multilingual performance, especially in French, Spanish, Italian, German, and Portuguese.
- Function calling requires
tool_choiceto be set — use"auto"for model-driven decisions. - JSON mode requires the system or user prompt to explicitly mention JSON output.