Moonshot

A large-context language model supporting extended input windows for deep document analysis and long-form reasoning. Excels at extracting insights from lengthy texts, cross-document synthesis, and complex multi-step tasks. Ideal for research assistance, legal document review, and technical analysis.

StepFun's flagship model for agentic work, delivering frontier-level performance on software engineering and professional knowledge work with particular strength in finance. Natively understands text, images, and video within a 1M token context window and returns up to 64K tokens per response, with low, medium, and high reasoning effort available. Built on a sparse mixture-of-experts design with 600B total parameters and 27B active, it suits workloads that need large amounts of input, repeated tool calls, and steady progress toward a finished deliverable.