Y Combinator was created by Paul Graham, Jessica Livingston, Robert Morris and Trevor Blackwell. The startup accelerator began in Cambridge, Massachusetts, in 2005 and later became based in Mountain View, California.
Y Combinator introduced a structured program in which selected startups received seed funding, guidance and access to a founder network. Companies typically worked toward a public Demo Day presentation for investors. Its model helped make accelerator programs a central part of modern startup culture.
Y Combinator is sometimes confused with Techstars or 500 Global because all three support early-stage companies. They are separate organizations with different origins and program histories. Y Combinator’s early portfolio included Reddit, and its application-driven batch system became influential across the global startup ecosystem.