Great products are built by great teams. Category-defining ones are built by people like our new Chief Scientist. Meet our Chief Scientist: Fei. Fei joins Donut from the frontier of AI, working at the intersection of intelligence and real-world systems. From Tsinghua, Caltech, to Fei has helped shape how AI interfaces with societal needs across clinical trials, political systems, and education, not just in theory, but through systems that actually operate in the real world. At Donut, that thinking sharpens into something bigger. If machines can think, they can act with self-hosted infra, and if they can act, they can move money in every market when prioritizing constraints. That’s the direction we’re building with D0. Also, Fei loves 'games' like IOI (International Olympiad in Informatics), which has accidentally become a good label for modern AI.