Grok 4.1 Fast vs Xiaomi MiMo-V2.5
Grok 4.1 Fast (2025) and Xiaomi MiMo-V2.5 (2026) are frontier-tier reasoning models from xAI and Xiaomi. Grok 4.1 Fast ships a 2m-token context window, while Xiaomi MiMo-V2.5 ships a 1.05m-token context window. On pricing, Xiaomi MiMo-V2.5 costs $0.14/1M input tokens versus $0.20/1M for the alternative. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Xiaomi MiMo-V2.5 is ~43% cheaper at $0.14/1M; pay for Grok 4.1 Fast only for long-context analysis.
Decision scorecard
Local evidence first| Signal | Grok 4.1 Fast | Xiaomi MiMo-V2.5 |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | reasoning-heavy apps, multimodal apps, and tool-calling agents |
| Decision fit | RAG, Agents, and Long context | RAG, Agents, and Long context |
| Context window | 2m | 1.05m |
| Cheapest output | $0.50/1M tokens | $0.28/1M 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.
- Local decision data tags Grok 4.1 Fast for RAG, Agents, and Long context.
- Xiaomi MiMo-V2.5 has the lower cheapest tracked output price at $0.28/1M tokens.
- Local decision data tags Xiaomi MiMo-V2.5 for RAG, Agents, and 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
Xiaomi MiMo-V2.5
$182
Cheapest tracked route/tier: OpenRouter
Estimated monthly gap: $103. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on OpenRouter; start route-level A/B tests there.
- Xiaomi MiMo-V2.5 is $0.22/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Provider overlap exists on OpenRouter; start route-level A/B tests there.
- Grok 4.1 Fast is $0.22/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-11-19 | 2026-04-22 |
| Context window | 2m | 1.05m |
| Parameters | — | — |
| Architecture | - | - |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Commercial use | Commercial use with conditions | Commercial use with conditions |
| Knowledge cutoff | - | - |
Pricing and availability
| Pricing attribute | Grok 4.1 Fast | Xiaomi MiMo-V2.5 |
|---|---|---|
| Input price | $0.20/1M tokens | $0.14/1M tokens |
| Output price | $0.50/1M tokens | $0.28/1M tokens |
| Providers |
Capabilities
| Capability | Grok 4.1 Fast | Xiaomi MiMo-V2.5 |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | Yes |
| Function calling | Yes | Yes |
| Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| 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 is close: both models cover vision, multimodal input, reasoning mode, function calling, and tool use. That makes context budget, benchmark fit, and provider maturity more important than a simple checklist. If your application depends on one integration detail, verify it against the provider route you plan to use, not just the base model listing.
For cost, Grok 4.1 Fast lists $0.20/1M input and $0.50/1M output tokens on the cheapest tracked provider, while Xiaomi MiMo-V2.5 lists $0.14/1M input and $0.28/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Xiaomi MiMo-V2.5 lower by about $0.11 per million blended tokens. Availability is 2 providers versus 2, so concentration risk also matters.
Choose Grok 4.1 Fast when long-context analysis and larger context windows are central to the workload. Choose Xiaomi MiMo-V2.5 when vision-heavy evaluation and lower input-token cost 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 Xiaomi MiMo-V2.5?
Grok 4.1 Fast supports 2m tokens, while Xiaomi MiMo-V2.5 supports 1.05m tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, Grok 4.1 Fast or Xiaomi MiMo-V2.5?
Xiaomi MiMo-V2.5 is cheaper on tracked token pricing. Grok 4.1 Fast costs $0.20/1M input and $0.50/1M output tokens. Xiaomi MiMo-V2.5 costs $0.14/1M input and $0.28/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Grok 4.1 Fast or Xiaomi MiMo-V2.5 open source?
Grok 4.1 Fast is listed under Proprietary. Xiaomi MiMo-V2.5 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 Xiaomi MiMo-V2.5?
Both Grok 4.1 Fast and Xiaomi MiMo-V2.5 expose vision. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for multimodal input, Grok 4.1 Fast or Xiaomi MiMo-V2.5?
Both Grok 4.1 Fast and Xiaomi MiMo-V2.5 expose multimodal input. 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 Xiaomi MiMo-V2.5?
Grok 4.1 Fast is available on OpenRouter and xAI Console. Xiaomi MiMo-V2.5 is available on OpenRouter and Xiaomi. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-05-26. Data sourced from public model cards and provider documentation.