Quang Hoang, the 37-year-old cofounder and CEO of San Francisco-based Vybe, has participated in Y Combinator (YC) twice: first in 2016 and again in 2025. His account reveals how the accelerator's core principles remain, but its scale, demographic, and thematic focus have transformed dramatically.
The French entrepreneur's first venture, a Slack bot for expense reports, was accepted after a live demonstration during the interview. The 2016 batch, then led by partners including Sam Altman and Paul Graham, was held in Mountain View with about 100 founders. "The core principle remained the same, but everything felt way less streamlined," Hoang noted, describing "family-style" dinners sometimes cooked by partners.
From Mobile Apps to AI: A Shift in Startup Themes
The most evident change is in the startups themselves. The 2016 cohort was dominated by mobile apps and cloud-based services. In contrast, the 2025 batch is heavily focused on artificial intelligence (AI). Hoang, returning with his new "vibe-coding" platform Vybe after his first company was acquired, observed this thematic pivot firsthand.
He also noted a significant shift in founder demographics. "You have more and more young founders... I was one of the old folks," he said, suggesting this trend has accelerated in the last two years. This aligns with YC's historical preference for "young founders that don't know limits," a trait he believes is equally valuable in the AI era.
Scale and Process: Growing Pains and Consistency
The batch size has roughly tripled, from approximately 100 founders a decade ago to around 300-400 today. Despite this, Hoang asserts the core experience—weekly dinners, group and individual office hours, and Demo Day—feels similar due to the subgroup structure. "If you are 300 or 400 people in the batch, it doesn't change that much," he explained.
The fundamental weekly growth requirements have intensified, rising from 5-10% in 2016 to 10-15% today. The pressure to "talk to users, code, and grow" every week remains the immutable core of the YC methodology.
Demo Day's Evolving Role and the YC Brand
One major evolution is the perceived importance of Demo Day, the accelerator's culminating investor event. "Demo Day was way more important at the time than it is today," Hoang stated. He now sees it primarily as an "anchor date" that creates urgency for investors to commit capital beforehand, as the most sought-after startups now secure funding well in advance.
Concurrently, the YC brand's power has grown substantially. "The brand is probably 10x better today than it was 10 years ago," Hoang estimated, providing a significant advantage for portfolio companies in fundraising and market recognition.
When asked if returning was the right decision, Hoang's answer was unequivocal: "It's 100% yes." His journey underscores Y Combinator's adaptation from a hands-on, intimate programme to a scaled, process-driven institution, while striving to maintain the founder-first ethos that sparked its legacy.