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StepFun: Step 3.5 Flash

stepfun/step-3.5-flash:free

Model 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.

Modalities

Price

Free

Context

256K

Released

Jan 29, 2026

Activity

Activity

Token volume and request traffic to this model over time.