Grok 4 Fast Reasoning vs Kimi K2.7-Code
Grok 4 Fast Reasoning (2025) and Kimi K2.7-Code (2026) compare a standalone API model against a coding-specialized model. Grok 4 Fast Reasoning ships a 2m-token context window, while Kimi K2.7-Code ships a 262k-token context window. On pricing, Kimi K2.7-Code costs $0.95/1M input tokens versus $1.25/1M for the alternative. This page treats the result as workflow and deployment fit, not a universal model winner.
Treat this as a product-type comparison: Grok 4 Fast Reasoning is standalone API model, while Kimi K2.7-Code is coding-specialized model. Choose based on workflow fit before reading any benchmark or price row as decisive.
Decision scorecard
Local evidence first| Signal | Grok 4 Fast Reasoning | Kimi K2.7-Code |
|---|---|---|
| Product type | Standalone API model | Coding-specialized model |
| Best for | reasoning-heavy apps, multimodal apps, and long-context analysis | custom coding agents, code generation, and tool loops |
| Decision fit | Long context and Vision | Coding, RAG, and Agents |
| Context window | 2m | 262k |
| Cheapest output | $2.50/1M tokens | $4/1M tokens |
| Provider routes | 2 tracked | 1 tracked |
| Shared benchmarks | 0 shared | 0 shared |
Decision tradeoffs
- Grok 4 Fast Reasoning has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Grok 4 Fast Reasoning has the lower cheapest tracked output price at $2.50/1M tokens.
- Grok 4 Fast Reasoning has broader tracked provider coverage for fallback and procurement flexibility.
- Local decision data tags Grok 4 Fast Reasoning for Long context and Vision.
- Kimi K2.7-Code uniquely exposes Function calling, Tool use, and Structured outputs in local model data.
- Local decision data tags Kimi K2.7-Code for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Grok 4 Fast Reasoning
$1,625
Cheapest tracked route/tier: xAI Console
Kimi K2.7-Code
$1,760
Cheapest tracked route/tier: Moonshot AI Kimi
Estimated monthly gap: $135. 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 Fast Reasoning and Kimi K2.7-Code; plan for SDK, billing, or endpoint changes.
- Kimi K2.7-Code is $1.50/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Kimi K2.7-Code adds Function calling, Tool use, and Structured outputs in local capability data.
- No overlapping tracked provider route is sourced for Kimi K2.7-Code and Grok 4 Fast Reasoning; plan for SDK, billing, or endpoint changes.
- Grok 4 Fast Reasoning is $1.50/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Function calling, Tool use, and Structured outputs before moving production traffic.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-09-01 | 2026-06-12 |
| Context window | 2m | 262k |
| Parameters | — | 1T |
| Architecture | Decoder Only | Mixture of Experts |
| License | Proprietary | MITOSI-approved |
| Openness | Proprietary | Open source |
| Commercial use | Commercial use: conditional | Commercial use: permitted |
| Knowledge cutoff | - | - |
Pricing and availability
| Pricing attribute | Grok 4 Fast Reasoning | Kimi K2.7-Code |
|---|---|---|
| Input price | $1.25/1M tokens | $0.95/1M tokens |
| Output price | $2.50/1M tokens | $4/1M tokens |
| Providers |
Capabilities
| Capability | Grok 4 Fast Reasoning | Kimi K2.7-Code |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | Yes |
| Function calling | No | Yes |
| Tool use | No | Yes |
| Structured outputs | No | Yes |
| Code execution | No | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark scores are currently available for this pair.
Deep dive
The capability footprint differs most on function calling: Kimi K2.7-Code, tool use: Kimi K2.7-Code, and structured outputs: Kimi K2.7-Code. Both models share vision, multimodal input, and 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.
For cost, Grok 4 Fast Reasoning lists $1.25/1M input and $2.50/1M output tokens on the cheapest tracked provider, while Kimi K2.7-Code lists $0.95/1M input and $4/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Grok 4 Fast Reasoning lower by about $0.24 per million blended tokens. Availability is 2 providers versus 1, so concentration risk also matters.
Choose Grok 4 Fast Reasoning when long-context analysis, larger context windows, and broader provider choice are central to the workload. Choose Kimi K2.7-Code when coding workflow support 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.
FAQ
Which has a larger context window, Grok 4 Fast Reasoning or Kimi K2.7-Code?
Grok 4 Fast Reasoning supports 2m tokens, while Kimi K2.7-Code supports 262k 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 Fast Reasoning or Kimi K2.7-Code?
Grok 4 Fast Reasoning is cheaper on tracked token pricing. Grok 4 Fast Reasoning costs $1.25/1M input and $2.50/1M output tokens. Kimi K2.7-Code costs $0.95/1M input and $4/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Grok 4 Fast Reasoning or Kimi K2.7-Code open source?
Grok 4 Fast Reasoning is listed under Proprietary. Kimi K2.7-Code is listed under MIT. 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 Fast Reasoning or Kimi K2.7-Code?
Both Grok 4 Fast Reasoning and Kimi K2.7-Code expose vision. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Which is better for multimodal input, Grok 4 Fast Reasoning or Kimi K2.7-Code?
Both Grok 4 Fast Reasoning and Kimi K2.7-Code 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 Fast Reasoning and Kimi K2.7-Code?
Grok 4 Fast Reasoning is available on Microsoft Foundry and xAI Console. Kimi K2.7-Code is available on Moonshot AI Kimi. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-06-14. Data sourced from public model cards and provider documentation.