Step 3.5 Flash
Stepfun
stepfun/step-3.5-flashStep 3.5 Flash is StepFun's flagship sparse MoE reasoning model (196B parameters, 11B active) built for fast, reliable execution of complex tasks. It excels at decomposing and planning multi-step problems and orchestrating tool calls, making it well suited for agentic and coding workflows.
Cost rate
0.1x
Context
262K
Released
Jan 29, 2026
Input
Text
Output
Text
Support
ReasoningTool callingStructured outputs
Best at
The categories where this model ranks highest.
Mathematical
#115 · top 31%
Software & IT Services
#137 · top 35%
Life, Physical, & Social Science
#154 · top 39%
Business, Management, & Finance
#154 · top 40%
Performance
Median latency and throughput measured across recent requests.
Throughput214 tok/s
Latency