Chinese artificial intelligence start-up StepFun has unveiled a lightweight AI model that it says punches above its weight, rivalling larger systems from domestic competitors including DeepSeek and Moonshot AI as competition intensifies in the country’s AI sector. The Shanghai-based AI lab said on Monday its latest Step 3.5 Flash model was designed to deliver advanced reasoning and agentic capabilities while maintaining efficiency. Despite its relatively modest size of about 196 billion...