Duolingo

Duolingo is an AI-first education company co-founded by Luis von Ahn and Severin Hacker, originating as a research project at Carnegie Mellon University . Its mission is to make high-quality education universally accessible by using technology to replicate one-on-one tutoring at near-zero marginal cost . The company went its first five years without revenue while prioritizing this mission over monetization .

Today Duolingo operates on a freemium model with roughly 130 million monthly active users, keeping core daily learning free while monetizing through tiered subscriptions (Free, Super, and Max) and advertising . Its growth engine is a culture of relentless experimentation—internally called the "Green Machine"—where features like the streak counter emerged from one test and were then optimized through hundreds of subsequent iterations . The company has leaned aggressively into AI: it was among OpenAI's first GPT-4 partners, uses ElevenLabs for voice technology, and in April 2025 announced a full AI-First restructuring that let it add 148 courses in one year after previously taking twelve years to build its first hundred . That move briefly triggered a subscriber backlash . Union Square Ventures led its Series A and remains its most cited helpful investor .