Garry Tan

Garry Tan (born 1981) is an American investor and designer-engineer who co-founded the blogging platform Posterous, joined Y Combinator as a partner in 2011, and co-founded Initialized Capital — where he was famously an early backer of Coinbase. In 2023 he returned to lead Y Combinator as president and CEO, putting him at the throughput point of Silicon Valley’s startup pipeline just as generative AI arrived.

The vibe coding batch

In March 2025 Tan posted the statistic that defined the moment: for a quarter of YC’s Winter 2025 batch, 95 percent of their code was LLM-generated. Adopting the term Andrej Karpathy had coined weeks earlier, he told CNBC the age of vibe coding meant ten engineers could now do the work of fifty to a hundred, and that the batch was growing faster than any in YC’s history. Under Tan, YC’s batches have tilted heavily toward AI startups, and he has urged founders to treat AI fluency as table stakes.

The claim drew immediate pushback from engineers who questioned the survey’s rigor and warned that AI-generated codebases carry hidden maintenance and security debt — a “vibe coding hangover” some developers say they are already billing hours to clean up. Tan concedes the tools fail at scale today but bets they will improve faster than the skeptics expect. He has also been a vocal, sometimes combative advocate for tech-friendly politics in San Francisco, framing AI as an American competitive imperative.