GPT-5.1 Codex High vs Kimi K2.8 Preview
Comparing GPT-5.1 Codex High and Kimi K2.8 Preview across benchmarks, pricing, and capabilities.
OpenAI · Moonshot AI · Updated for 2026
Which is better?
GPT-5.1 Codex High and Kimi K2.8 Preview trade strengths across price, capabilities, and technical limits. The better choice depends on the workload.
Kimi K2.8 Preview also accepts a larger context window (1,048,576 input tokens), making it the stronger choice for long documents and large codebases.
Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.
Choose GPT-5.1 Codex High
- you want predictable pricing at $1.25/M input and $10.00/M output
Choose Kimi K2.8 Preview
- you process long inputs — it offers a 1,048,576 token context window
- you want the most recent training data — it shipped Sep 2026
At a glance
The differences that matter most.
Individual benchmarks
1 reported for GPT-5.1 Codex High · 0 for Kimi K2.8 Preview
GPT-5.1 Codex High and Kimi K2.8 Previewdon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.
Human preference
Blind head-to-head votes and playground preference scores
Context Window
Maximum input and output token capacity
Kimi K2.8 Preview accepts 1,048,576 input tokens compared to GPT-5.1 Codex High's 400,000 tokens. Only GPT-5.1 Codex High specifies output context (128,000 tokens).
Input capabilities
Documented input modalities across available providers
Both GPT-5.1 Codex High and Kimi K2.8 Preview support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
GPT-5.1 Codex High
Kimi K2.8 Preview
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
GPT-5.1 Codex High was released on 2025-11-12, while Kimi K2.8 Preview was released on 2026-09-11.
Kimi K2.8 Preview is 10 months newer than GPT-5.1 Codex High.
Nov 12, 2025
10 months ago
Sep 11, 2026
5 days ago
10mo newerKnowledge Cutoff
When training data ends
Neither model specifies a knowledge cutoff date.
Unable to compare the recency of their training data.
Provider Availability
GPT-5.1 Codex High is available from OpenAI. Kimi K2.8 Preview is available from Moonshot AI.
GPT-5.1 Codex High
Kimi K2.8 Preview
Outputs Comparison
Judge for yourself.
Run your own prompts against GPT-5.1 Codex High and Kimi K2.8 Preview side-by-side, then vote on the output you prefer.
FAQ
Common questions about GPT-5.1 Codex High vs Kimi K2.8 Preview.