Magistral Small 2509
Magistral Small 2509 is a 24B open-source reasoning model under Apache 2.0 with 70.7% on AIME 2024. It's Mistral AI's compact reasoning option in the Magistral family.
import { streamText } from 'ai'
const result = streamText({ model: 'mistral/magistral-small', prompt: 'Why is the sky blue?'})Playground
Try out Magistral Small 2509 by Mistral AI. Usage is billed to your team at API rates. Free users (those who haven't made a payment) get $5 of credits every 30 days.
Magistral Small 2509
Ask Magistral Small 2509 anything to try it out.
Providers
Route requests across multiple providers. Copy a provider slug to set your preference. Visit the docs for more info. Using a provider means you agree to their terms, listed under Legal.
| Provider |
|---|
Mistral AI | 128K | 0.3s | 85tps | $0.50/M | $1.50/M | — | — | +1 | 06/10/2025 |
P50 throughput on live AI Gateway traffic, in tokens per second (TPS). Visit the docs for more info.
P50 time to first token (TTFT) on live AI Gateway traffic, in milliseconds. View the docs for more info.
Direct request success rate on AI Gateway and per-provider. Visit the docs for more info.
More models by Mistral AI
| Model |
|---|
| 256K | 0.6s | 39tps | $0.10/M | $0.30/M | — | — | | 12/09/2025 | |||||
| 256K | 0.5s | 59tps | $0.50/M | $1.50/M | — | — | | 12/02/2025 | |||||
| 256K | 0.5s | 83tps | $0.20/M | $0.20/M | — | — | +1 | | 12/02/2025 | ||||
| 128K | 0.3s | 156tps | $0.10/M | $0.10/M | — | — | | 10/16/2024 | |||||
| 32K | 0.4s | 168tps | $0.10/M | $0.30/M | — | — | | 09/17/2024 | |||||
| $0.10/M | — | — | | 12/11/2023 |
About Magistral Small 2509
Magistral Small 2509 was announced alongside Magistral Medium on June 10, 2025 as the open-source counterpart in Mistral AI's first reasoning model release. At 24B parameters, it scores 70.7% on AIME 2024 and 83.3% with majority voting.
Like Magistral Medium, Magistral Small 2509 produces transparent chain-of-thought reasoning and covers the same eight languages: English, French, Spanish, German, Italian, Arabic, Russian, and Simplified Chinese. It applies reasoning depth to business strategy, regulated industries, software engineering, and creative applications, rather than functioning as a smaller instruct model.
The Apache 2.0 license means weights are available on Hugging Face for commercial use.
What To Consider When Choosing a Provider
- Configuration: Magistral Small 2509's Apache 2.0 license makes it the only reasoning model in the Magistral family that can be freely incorporated into commercial products without a separate licensing agreement.
- Zero Data Retention: AI Gateway supports Zero Data Retention for this model via direct gateway requests (BYOK is not included). To configure this, check the documentation.
- Authentication: AI Gateway authenticates requests using an API key or OIDC token. You do not need to manage provider credentials directly.
When to Use Magistral Small 2509
Best For
- Apache 2.0 commercial products: Need this license for reasoning model integration
- Cost-sensitive reasoning workloads: Applications where the 70.7% AIME 2024 score is sufficient
- Research and educational use: Cases requiring transparent, auditable reasoning
Consider Alternatives When
- Highest reasoning accuracy: You need the top option (consider Magistral Medium at 73.6%)
- No structured reasoning needed: The task does not require multi-step reasoning at all
Conclusion
Magistral Small 2509 reaches 70.7% on AIME 2024 with transparent chain-of-thought and Apache 2.0 licensing. Access it through AI Gateway for reasoning workloads without proprietary model lock-in.