StepFunStep 3
#80StepFun: Step 3.5 Flash (free)
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.
Context
256K
Max Output
256K
Input/1M
Free
🧠 Reasoning🔧 Tools
Pricing (per 1M tokens)
OpenRouterFree / Free
Martian$0.10 / $0.30
2026-01-29View details →