Duolingo is a mission-driven technology company that develops AI-powered language-learning and educational platforms to make high-quality learning universally accessible through a mobile-first, freemium model. The company's flagship Duolingo app is the world's most popular language-learning platform, monetized through subscriptions (Super Duolingo and Duolingo Max) and in-app advertising from free users, while the Duolingo English Test provides online English proficiency assessment used by education institutions and employers globally. The business model leverages reinforcing flywheels: a learning flywheel where scale generates proprietary data that powers personalized AI-driven instruction and product improvements, and an investment flywheel where organic growth enables capital allocation toward innovation rather than marketing, supported by gamified lesson design, bite-sized content, and adaptive difficulty that drive strong user retention and virality.