Z Fellows is a one-week fellowship and accelerator for very early technical builders, founded by Cory Levy. It runs rolling cohorts that are mostly virtual, with an in-person final day in San Francisco or New York. Participants receive mentorship from experienced technology founders and investors and may optionally take a $10,000 investment through a convertible instrument with a $1 billion valuation cap. The program works with builders across AI, consumer, enterprise, defense, healthcare, fintech, climate, biotech, and other sectors.