Y Combinator is a startup accelerator founded in 2005 that invests $500,000 in early-stage companies in exchange for equity, then runs them through an intensive three-month program in San Francisco capped by a Demo Day pitch to investors. It has funded more than 5,000 companies - including Airbnb, Stripe, Coinbase, DoorDash, Dropbox, Reddit, Instacart and Twitch - whose combined value tops $600 billion, making YC the most influential template for how modern software startups get built and funded.

Paul Graham is a programmer, essayist, and co-founder of Y Combinator, the seed accelerator that launched Airbnb, Stripe, Dropbox, Reddit, and OpenAI. He sold his first startup Viaweb to Yahoo for $49.6 million in 1998, then used that platform to build one of the most influential idea-factories in tech history. His essays at paulgraham.com have become the de facto canon of startup culture, read by millions of founders seeking clarity on how to build, think, and live.