GPT-5.1 Codex Max vs Kimi K2.7-Code
GPT-5.1 Codex Max (2025) and Kimi K2.7-Code (2026) are agentic coding models from OpenAI and Moonshot AI. GPT-5.1 Codex Max ships a not-yet-sourced context window, while Kimi K2.7-Code ships a 262k-token context window. On pricing, Kimi K2.7-Code costs $0.61/1M input tokens versus $1.25/1M 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.
Kimi K2.7-Code is ~104% cheaper at $0.61/1M; pay for GPT-5.1 Codex Max only for coding workflow support.
Decision scorecard
Local evidence first| Signal | GPT-5.1 Codex Max | Kimi K2.7-Code |
|---|---|---|
| Best for | custom coding agents, code generation, and tool loops | custom coding agents, code generation, and tool loops |
| Decision fit | Coding, Agents, and Vision | Coding, RAG, and Agents |
| Context window | — | 262k |
| Cheapest output | $10/1M tokens | $3.07/1M tokens |
| Provider routes | 1 tracked | 2 tracked |
| Shared benchmarks | 0 shared | 0 shared |
Decision tradeoffs
- Local decision data tags GPT-5.1 Codex Max for Coding, Agents, and Vision.
- Kimi K2.7-Code has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Kimi K2.7-Code has the lower cheapest tracked output price at $3.07/1M tokens.
- Kimi K2.7-Code has broader tracked provider coverage for fallback and procurement flexibility.
- 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.
GPT-5.1 Codex Max
$3,500
Cheapest tracked route/tier: Vercel AI Gateway
Kimi K2.7-Code
$1,257
Cheapest tracked route/tier: OpenRouter
Estimated monthly gap: $2,243. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- No overlapping tracked provider route is sourced for GPT-5.1 Codex Max and Kimi K2.7-Code; plan for SDK, billing, or endpoint changes.
- Kimi K2.7-Code is $6.93/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- No overlapping tracked provider route is sourced for Kimi K2.7-Code and GPT-5.1 Codex Max; plan for SDK, billing, or endpoint changes.
- GPT-5.1 Codex Max is $6.93/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-11-19 | 2026-06-12 |
| Context window | — | 262k |
| Parameters | — | 1T |
| Architecture | - | Mixture of Experts |
| License | Proprietary | MITOSI-approved |
| Openness | Proprietary | Open source |
| Commercial use | Commercial use: conditional | Commercial use: permitted |
| Knowledge cutoff | 2024-09 | - |
Pricing and availability
| Pricing attribute | GPT-5.1 Codex Max | Kimi K2.7-Code |
|---|---|---|
| Input price | $1.25/1M tokens | $0.61/1M tokens |
| Output price | $10/1M tokens | $3.07/1M tokens |
| Providers |
Capabilities
| Capability | GPT-5.1 Codex Max | Kimi K2.7-Code |
|---|---|---|
| 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 scores are currently available 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, GPT-5.1 Codex Max lists $1.25/1M input and $10/1M output tokens on the cheapest tracked provider, while Kimi K2.7-Code lists $0.61/1M input and $3.07/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Kimi K2.7-Code lower by about $2.53 per million blended tokens. Availability is 1 providers versus 2, so concentration risk also matters.
Choose GPT-5.1 Codex Max when coding workflow support are central to the workload. Choose Kimi K2.7-Code when coding workflow support, lower input-token cost, and broader provider choice 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 is cheaper, GPT-5.1 Codex Max or Kimi K2.7-Code?
Kimi K2.7-Code is cheaper on tracked token pricing. GPT-5.1 Codex Max costs $1.25/1M input and $10/1M output tokens. Kimi K2.7-Code costs $0.61/1M input and $3.07/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is GPT-5.1 Codex Max or Kimi K2.7-Code open source?
GPT-5.1 Codex Max 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, GPT-5.1 Codex Max or Kimi K2.7-Code?
Both GPT-5.1 Codex Max 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. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for multimodal input, GPT-5.1 Codex Max or Kimi K2.7-Code?
Both GPT-5.1 Codex Max 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.
Which is better for reasoning mode, GPT-5.1 Codex Max or Kimi K2.7-Code?
Both GPT-5.1 Codex Max and Kimi K2.7-Code 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 GPT-5.1 Codex Max and Kimi K2.7-Code?
GPT-5.1 Codex Max is available on Vercel AI Gateway. Kimi K2.7-Code is available on Moonshot AI Kimi and OpenRouter. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-06-25. Data sourced from public model cards and provider documentation.