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.
LangRouter routes requests to the best providers that are able to handle your prompt size and parameters.
openrouter/step-3.5-flash:free