YC

Y Combinator (YC) is an American seed-stage startup accelerator that provides funding, mentorship, and a supportive network to early-stage companies. It was founded in 2005 by Paul Graham, Jessica Livingston, Robert T. Morris, and Trevor Blackwell. Since its inception, YC has funded thousands of startups and helped establish a model that has been imitated globally.

YC runs two three-month cohorts each year, typically based in the San Francisco Bay Area. Participating teams receive mentorship, office hours, and access to a network of alumni and investors. The program culminates in Demo Day, when founders present their progress to a targeted audience of investors. Funding is provided in exchange for equity, usually via a simple convertible instrument with terms set at the outset.

Alumni and impact: YC is known for its large and active alumni network, ongoing support through its Continuity and Research initiatives, and a track record of producing highly successful technology companies. Notable YC alumni include Airbnb, Dropbox, Stripe, Reddit, DoorDash, and Instacart.

History: The program began in Cambridge, Massachusetts, moved to the Bay Area as it grew, and expanded to include a global network of partners and programs. YC's model emphasizes rapid iteration, product-market fit, and hands-on mentorship, and it has influenced how early-stage funding and mentorship are delivered in the startup ecosystem.