Y Combinator (YC) is a startup fund and program. Since 2005, YC has invested in nearly 3,000 companies including Airbnb, DoorDash, Stripe, Instacart, Dropbox, and Coinbase. The combined valuation of YC companies is over $300B. YC has programs and resources that support founders throughout the life of their company. Startup School teaches the basics of starting a company. The YC batch program helps founders as they build their product, talk to their customers, and raise funding. Work at a Startup makes it easy for founders to find their first engineers. YC Series A helps founders launch their A round. YC Growth Program provides founders with resources to scale their companies and hire an executive team, and YC Continuity invests in their later stage rounds.