StepFun

StepFun text reasoning model for agents, coding, tool calling, and long-context analysis.

Agent-optimized Step 3.5 Flash variant with low and high reasoning effort modes.

StepFun multimodal reasoning model with image and video input, tool calling, adjustable reasoning effort, and 256K context.

StepFun image generation and image editing model for text-to-image and single-image edits.

StepFun text-to-speech model with official voices, custom cloned voices, and voice tag controls.

StepFun streaming speech recognition model for Chinese and English audio transcription.

StepFun audio and text conversation model with text output and paralinguistic understanding.

Contextual StepFun text-to-speech model with natural-language voice direction and expressive delivery.