Jang Young-jun

Riiid develops AI-powered adaptive learning and test preparation technology, most notably the Santa TOEIC app, which uses reinforcement learning and knowledge tracing algorithms to personalise English proficiency test preparation for individual learners based on their demonstrated strengths and weaknesses. The Seoul company builds AI models that predict which questions each student should practice to maximise test score improvement per unit of study time.\n\nThe company raised approximately $220 million including a Series D from investors including SoftBank Ventures Asia, Owl Ventures, and GoodWater Capital, reaching a valuation exceeding $1 billion. Riiid Santa TOEIC app has been used by millions of Korean learners preparing for the TOEIC English proficiency exam, which is a mandatory or strongly encouraged credential for employment at major Korean corporations. The company has expanded its AI tutoring technology beyond TOEIC into other standardised test preparation and enterprise training applications.\n\nRiiid competes in the AI education market against Duolingo, Khan Academy, and Korean education technology companies including Classting and Mathpresso. Its reinforcement learning-based adaptive learning system, which optimises study sequences for individual score improvement rather than presenting content in a fixed curriculum order, represents a technically sophisticated approach to personalised learning that distinguishes it from content-first edtech platforms. The proven consumer use case in TOEIC preparation provides a revenue foundation and model validation that the company is extending into new learning domains.