CodeSignal is a San Francisco-based skills platform that uses AI-driven simulations to assess technical and soft-skills talent and to train workers through Cosmo, its conversational AI tutor. Founded in 2015 as CodeFights and rebranded in 2018, it now powers technical hiring and upskilling at companies like Meta, Netflix, Zoom, Robinhood and Capital One.
Quizlet is an American education technology company that built the world's most-used flashcard app and is now retooling itself as an AI-powered study coach. Founded in 2005 by a 15-year-old high schooler studying for a French final, it has grown into a platform used by tens of millions of students each month across more than 130 countries.
Speak is an AI-powered language learning app that gets users speaking out loud from day one. Backed by OpenAI's Startup Fund, Accel, Khosla Ventures and Y Combinator, the San Francisco company reached unicorn status in December 2024 after raising a $78M Series C at a $1B valuation. Its AI tutor offers unlimited conversational practice and instant feedback to over 10 million learners.
YouLearn is an AI-powered personalized tutoring platform built by students, for students. Founded by three college friends frustrated with outdated lecture videos and generic AI tools, YouLearn transforms any learning material - PDFs, YouTube videos, lecture slides, even photos - into concise notes, adaptive quizzes, and an interactive AI tutor. With 2M+ users globally, $770K ARR, and backing from Y Combinator's Spring 2025 batch, YouLearn is building what they call a modern-day Aristotle: a lifelong AI tutor that grows alongside each student.