All Models

Stepfun/Step-3.5 Flash

Reasoning Tool Calling Attachments Open Weights

Step 3.5 Flash is StepFun's most capable open-source foundation model. Built on a sparse Mixture of Experts (MoE) architecture, it selectively activates only 11B of its 196B parameters per token. It is a reasoning model that is incredibly speed efficient even at long contexts.

Providers 2
Released Jan 29, 2026
Input Modalities text, image
Output Modalities text
Tarsk Use coding

Benchmarks

37.8
Intelligence Index
31.6
Coding Index

Available Providers (2)

Provider Model ID Input Cost Output Cost Context Max Output Docs
Kilo Gateway stepfun/step-3.5-flash $0.10/MTok $0.30/MTok 256K 256K
Qiniu stepfun/step-3.5-flash —/MTok —/MTok 64K 4.1K

Capabilities

Reasoning
Tool Calling
Attachments
Open Weights
Structured Output