Viacheslav Derzhaiev is the founder of Reasonal, an iOS app that teaches critical thinking through human-written, research-backed lessons. He designed, built, and shipped it as a solo founder, and continues to develop it against usage data and user feedback. He is also a Senior Product Designer at Course Hero, part of Learneo, a platform of six learning and productivity brands serving over 100 million monthly active users. Earlier he co-founded Rupt, a fintech startup, where he led product design and UX research. Before moving into product design, Viacheslav worked in management consulting at Bain & Company and in advertising at BBDO and Leo Burnett, a background that shapes how he connects design decisions to business outcomes and brand strategy. His work on web platforms and mobile applications has been recognized at Awwwards, the Indigo Design Award, the WorldWiDE EdTech Awards, the NY Product Design Awards, and the London Design Awards. He also judges the MUSE Design Awards, writes about product design on HackerNoon, and publishes open Figma resources used by other designers.