StepFun 3.5 Flash
StepFun 3.5 Flash is an open-source sparse MoE reasoning model from StepFun with 196B total parameters and about 11B active per token. It supports a context window of 262.1K tokens and a max output of 262.1K tokens per request.
ReasoningTool UseImplicit Caching
index.ts
import { streamText } from 'ai'
const result = streamText({ model: 'stepfun/step-3.5-flash', prompt: 'Why is the sky blue?'})More models by StepFun
| Model |
|---|
| 256K | 6.5s | 170tps | $0.20/M | $1.15/M | Read:$0.04/M Write:— | — | — | +2 |  | 05/28/2026 |