Skip to content
Log In
Sign Up
Dashboard

StepFun 3.5 Flash

Step 3.5 Flash is an open-source reasoning model by StepFun with 196B total parameters (11B active) using Mixture of Experts. It features a 256K context window, deep reasoning, tool calling, and agentic capabilities, achieving 97.3 on AIME 2025 and 74.4% on SWE-bench Verified.

ReasoningTool UseImplicit Caching
index.ts
import { streamText } from 'ai'


const result = streamText({
  model: 'stepfun/step-3.5-flash',
  prompt: 'Why is the sky blue?'
})
OverviewPlaygroundProvidersThroughputLatencyUptimeStatusSimilar