Kimi K2.8 Preview vs Step-3.5-Flash
Comparing Kimi K2.8 Preview and Step-3.5-Flash across benchmarks, pricing, and capabilities.
Moonshot AI · StepFun · Updated for 2026
Which is better?
Kimi K2.8 Preview and Step-3.5-Flash 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 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
Choose Step-3.5-Flash
- you need open weights you can self-host or fine-tune
At a glance
The differences that matter most.
Individual benchmarks
0 reported for Kimi K2.8 Preview · 7 for Step-3.5-Flash
Kimi K2.8 Preview and Step-3.5-Flashdon'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 Step-3.5-Flash's 65,536 tokens. Only Step-3.5-Flash specifies output context (8,192 tokens).
Input capabilities
Documented input modalities across available providers
Kimi K2.8 Preview supports multimodal inputs, whereas Step-3.5-Flash does not.
Kimi K2.8 Preview can handle both text and other forms of data like images, making it suitable for multimodal applications.
Kimi K2.8 Preview
Step-3.5-Flash
License
Usage and distribution terms
Kimi K2.8 Preview is licensed under a proprietary license, while Step-3.5-Flash uses Apache 2.0.
License differences may affect how you can use these models in commercial or open-source projects.
Proprietary
Closed source
Apache 2.0
Open weights
Release Timeline
When each model was launched
Kimi K2.8 Preview was released on 2026-09-11, while Step-3.5-Flash was released on 2026-02-02.
Kimi K2.8 Preview is 7 months newer than Step-3.5-Flash.
Sep 11, 2026
1 weeks ago
7mo newerFeb 2, 2026
7 months ago
Knowledge Cutoff
When training data ends
Neither model specifies a knowledge cutoff date.
Unable to compare the recency of their training data.
Provider Availability
Kimi K2.8 Preview is available from Moonshot AI. Step-3.5-Flash is available from StepFun.
Kimi K2.8 Preview
Step-3.5-Flash
Outputs Comparison
Judge for yourself.
Run your own prompts against Kimi K2.8 Preview and Step-3.5-Flash side-by-side, then vote on the output you prefer.
FAQ
Common questions about Kimi K2.8 Preview vs Step-3.5-Flash.