Grok 4.1 Fast vs Magistral Small 2506
Grok 4.1 Fast (2025) and Magistral Small 2506 (2025) are frontier-tier reasoning models from xAI and MistralAI. Grok 4.1 Fast ships a 2M-token context window, while Magistral Small 2506 ships a 128K-token context window. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit. It focuses on practical selection signals rather than broad model-family marketing. The goal is to make the tradeoff clear before deeper testing.
Grok 4.1 Fast fits 16x more tokens; pick it for long-context work and Magistral Small 2506 for tighter calls.
Decision scorecard
Local evidence first| Signal | Grok 4.1 Fast | Magistral Small 2506 |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | reasoning-heavy apps |
| Decision fit | RAG, Agents, and Long context | Long context |
| Context window | 2M | 128K |
| Cheapest output | $0.50/1M tokens | - |
| Provider routes | 2 tracked | 1 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 broader tracked provider coverage for fallback and procurement flexibility.
- Grok 4.1 Fast uniquely exposes Vision, Multimodal, and Function calling in local model data.
- Local decision data tags Grok 4.1 Fast for RAG, Agents, and Long context.
- Local decision data tags Magistral Small 2506 for Long context.
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
Magistral Small 2506
Unavailable
No complete token price in local provider data
Cost delta unavailable until both models have sourced input and output token prices.
Switch friction
- No overlapping tracked provider route is sourced for Grok 4.1 Fast and Magistral Small 2506; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Vision, Multimodal, and Function calling before moving production traffic.
- No overlapping tracked provider route is sourced for Magistral Small 2506 and Grok 4.1 Fast; plan for SDK, billing, or endpoint changes.
- Grok 4.1 Fast adds Vision, Multimodal, and Function calling in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-11-19 | 2025-06-10 |
| Context window | 2M | 128K |
| Parameters | — | 24B |
| Architecture | - | decoder only |
| License | Proprietary | Proprietary |
| Knowledge cutoff | - | 2025-06 |
Pricing and availability
| Pricing attribute | Grok 4.1 Fast | Magistral Small 2506 |
|---|---|---|
| Input price | $0.20/1M tokens | - |
| Output price | $0.50/1M tokens | - |
| Providers |
Capabilities
| Capability | Grok 4.1 Fast | Magistral Small 2506 |
|---|---|---|
| Vision | Yes | No |
| Multimodal | Yes | No |
| Reasoning | Yes | Yes |
| 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, function calling: Grok 4.1 Fast, tool use: Grok 4.1 Fast, and structured outputs: Grok 4.1 Fast. Both models share reasoning mode, 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.
Pricing coverage is uneven: Grok 4.1 Fast has $0.20/1M input tokens and Magistral Small 2506 has no token price sourced yet. Provider availability is 2 tracked routes versus 1. Treat unknown pricing as an integration gap, then verify the route you will actually call before estimating production spend.
Choose Grok 4.1 Fast when long-context analysis, larger context windows, and broader provider choice are central to the workload. Choose Magistral Small 2506 when provider fit are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions. It also helps separate model capability from provider packaging, which can change cost and latency.
FAQ
Which has a larger context window, Grok 4.1 Fast or Magistral Small 2506?
Grok 4.1 Fast supports 2M tokens, while Magistral Small 2506 supports 128K tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Is Grok 4.1 Fast or Magistral Small 2506 open source?
Grok 4.1 Fast is listed under Proprietary. Magistral Small 2506 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 Magistral Small 2506?
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 Magistral Small 2506?
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 Magistral Small 2506?
Both Grok 4.1 Fast and Magistral Small 2506 expose reasoning mode. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Where can I run Grok 4.1 Fast and Magistral Small 2506?
Grok 4.1 Fast is available on OpenRouter and xAI Console. Magistral Small 2506 is available on NVIDIA NIM. 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.