GPT-5.3-Codex-Spark vs Kimi K2.6
GPT-5.3-Codex-Spark (2026) and Kimi K2.6 (2026) are agentic coding models from OpenAI and Moonshot AI. GPT-5.3-Codex-Spark ships a 131k-token context window, while Kimi K2.6 ships a 262k-token context window. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads. It focuses on practical selection signals rather than broad model-family marketing.
Kimi K2.6 is safer overall; choose GPT-5.3-Codex-Spark when coding workflow support matters.
Decision scorecard
Local evidence first| Signal | GPT-5.3-Codex-Spark | Kimi K2.6 |
|---|---|---|
| Best for | custom coding agents, code generation, and tool loops | custom coding agents, code generation, and tool loops |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 131k | 262k |
| Cheapest output | - | $3.49/1M tokens |
| Provider routes | 1 tracked | 9 tracked |
| Shared benchmarks | 0 shared | 0 shared |
Decision tradeoffs
- GPT-5.3-Codex-Spark uniquely exposes Code execution in local model data.
- Local decision data tags GPT-5.3-Codex-Spark for Coding, RAG, and Agents.
- Kimi K2.6 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Kimi K2.6 has broader tracked provider coverage for fallback and route flexibility.
- Kimi K2.6 uniquely exposes Vision, Multimodal, and Reasoning in local model data.
- Local decision data tags Kimi K2.6 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-5.3-Codex-Spark
Unavailable
No complete token price in local provider data
Kimi K2.6
$1,457
Cheapest tracked route/tier: OpenRouter
Cost delta unavailable until both models have sourced input and output token prices.
Switch friction
- No overlapping tracked provider route is sourced for GPT-5.3-Codex-Spark and Kimi K2.6; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Code execution before moving production traffic.
- Kimi K2.6 adds Vision, Multimodal, and Reasoning in local capability data.
- No overlapping tracked provider route is sourced for Kimi K2.6 and GPT-5.3-Codex-Spark; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Vision, Multimodal, and Reasoning before moving production traffic.
- GPT-5.3-Codex-Spark adds Code execution in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-02-12 | 2026-04-20 |
| Context window | 131k | 262k |
| Parameters | — | 1T |
| Architecture | Decoder Only | Mixture of Experts |
| License | Proprietary | MITOSI-approved |
| Openness | Proprietary | Open source |
| Weights | Not released | Available·Moonshot Modified MIT License |
| Code | Unknown | Available·Moonshot Modified MIT License |
| Commercial use | Commercial use: conditional | Commercial use: permitted |
| Knowledge cutoff | - | 2025-04 |
Pricing and availability
| Pricing attribute | GPT-5.3-Codex-Spark | Kimi K2.6 |
|---|---|---|
| Input price | - | $0.73/1M tokens |
| Output price | - | $3.49/1M tokens |
| Providers |
Capabilities
| Capability | GPT-5.3-Codex-Spark | Kimi K2.6 |
|---|---|---|
| Vision | No | Yes |
| Multimodal | No | Yes |
| Reasoning | No | Yes |
| JSON / Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | Yes | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark scores are currently available for this pair.
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Last reviewed: 2026-06-30. Data sourced from public model cards and provider documentation.