Grok 4.1 Fast vs Mistral Magistral Small 2509
Grok 4.1 Fast (2025) and Mistral Magistral Small 2509 (2025) are frontier reasoning models from xAI and MistralAI. Grok 4.1 Fast ships a 2M-token context window, while Mistral Magistral Small 2509 ships a not-yet-sourced context window. On pricing, Grok 4.1 Fast costs $0.20/1M input tokens versus $0.50/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
Grok 4.1 Fast is ~150% cheaper at $0.20/1M; pay for Mistral Magistral Small 2509 only for provider fit.
Decision scorecard
Local evidence first| Signal | Grok 4.1 Fast | Mistral Magistral Small 2509 |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | provider-routed production |
| Decision fit | RAG, Agents, and Long context | General |
| Context window | 2M | — |
| Cheapest output | $0.50/1M tokens | $1.50/1M tokens |
| Provider routes | 2 tracked | 2 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- Grok 4.1 Fast has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Grok 4.1 Fast has the lower cheapest tracked output price at $0.50/1M tokens.
- Grok 4.1 Fast uniquely exposes Vision, Multimodal, and Reasoning in local model data.
- Local decision data tags Grok 4.1 Fast for RAG, Agents, and Long context.
- Use Mistral Magistral Small 2509 when your own prompt tests beat the comparison signals; the local data does not show a decisive standalone advantage yet.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Grok 4.1 Fast
$285
Cheapest tracked route/tier: OpenRouter
Mistral Magistral Small 2509
$775
Cheapest tracked route/tier: AWS Bedrock
Estimated monthly gap: $490. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- No overlapping tracked provider route is sourced for Grok 4.1 Fast and Mistral Magistral Small 2509; plan for SDK, billing, or endpoint changes.
- Mistral Magistral Small 2509 is $1/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Check replacement coverage for Vision, Multimodal, and Reasoning before moving production traffic.
- No overlapping tracked provider route is sourced for Mistral Magistral Small 2509 and Grok 4.1 Fast; plan for SDK, billing, or endpoint changes.
- Grok 4.1 Fast is $1/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Grok 4.1 Fast adds Vision, Multimodal, and Reasoning in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-11-19 | 2025-09-01 |
| Context window | 2M | — |
| Parameters | — | 24B |
| Architecture | - | - |
| License | Proprietary | Proprietary |
| Knowledge cutoff | - | - |
Pricing and availability
| Pricing attribute | Grok 4.1 Fast | Mistral Magistral Small 2509 |
|---|---|---|
| Input price | $0.20/1M tokens | $0.50/1M tokens |
| Output price | $0.50/1M tokens | $1.50/1M tokens |
| Providers |
Capabilities
| Capability | Grok 4.1 Fast | Mistral Magistral Small 2509 |
|---|---|---|
| Vision | Yes | No |
| Multimodal | Yes | No |
| Reasoning | Yes | No |
| Function calling | Yes | No |
| Tool use | Yes | No |
| Structured outputs | Yes | No |
| Code execution | No | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on vision: Grok 4.1 Fast, multimodal input: Grok 4.1 Fast, reasoning mode: Grok 4.1 Fast, function calling: Grok 4.1 Fast, tool use: Grok 4.1 Fast, and structured outputs: Grok 4.1 Fast. Both models share the core language-model surface, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
For cost, Grok 4.1 Fast lists $0.20/1M input and $0.50/1M output tokens on the cheapest tracked provider, while Mistral Magistral Small 2509 lists $0.50/1M input and $1.50/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Grok 4.1 Fast lower by about $0.51 per million blended tokens. Availability is 2 providers versus 2, so concentration risk also matters.
Choose Grok 4.1 Fast when reasoning depth and lower input-token cost are central to the workload. Choose Mistral Magistral Small 2509 when provider fit are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Which is cheaper, Grok 4.1 Fast or Mistral Magistral Small 2509?
Grok 4.1 Fast is cheaper on tracked token pricing. Grok 4.1 Fast costs $0.20/1M input and $0.50/1M output tokens. Mistral Magistral Small 2509 costs $0.50/1M input and $1.50/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Grok 4.1 Fast or Mistral Magistral Small 2509 open source?
Grok 4.1 Fast is listed under Proprietary. Mistral Magistral Small 2509 is listed under Proprietary. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for vision, Grok 4.1 Fast or Mistral Magistral Small 2509?
Grok 4.1 Fast has the clearer documented vision signal in this comparison. If vision is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for multimodal input, Grok 4.1 Fast or Mistral Magistral Small 2509?
Grok 4.1 Fast has the clearer documented multimodal input signal in this comparison. If multimodal input is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for reasoning mode, Grok 4.1 Fast or Mistral Magistral Small 2509?
Grok 4.1 Fast has the clearer documented reasoning mode signal in this comparison. If reasoning mode is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run Grok 4.1 Fast and Mistral Magistral Small 2509?
Grok 4.1 Fast is available on OpenRouter and xAI Console. Mistral Magistral Small 2509 is available on AWS Bedrock and Vercel AI Gateway. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-05-22. Data sourced from public model cards and provider documentation.