Sixtyfour AI is now backed by Y Combinator
The story behind building Sixtyfour AI, taking the leap, and what getting into YC really means to us.
Picture of us at the Y Combinator office in Mountain View, CA
What is Y Combinator?
Y Combinator is the world’s most selective startup accelerator, with an acceptance rate under 1%. Since 2005, YC has funded over 5,000 companies—including Airbnb, Dropbox, Stripe, and Coinbase—whose combined portfolio valuation now exceeds $800 billion.
But YC’s real power is in the community. The alumni network is one of the strongest out there, filled with some of the most ambitious and impactful founders in the world.
What YC Means to Us
Between the two of us, Chris and I had applied to YC 10 times. We were always close—never quite made it. I first applied as a freshman in college, full of energy but nowhere near ready. I actually heard about YC back in middle school in India. To me, it symbolized the American Dream.
Over the years, we tried dozens of ideas, worked at YC companies, and kept learning. We never gave up, even when it felt like we were always one step away.
This time, it just clicked and we are beyond excited to be part of YC’s first-ever spring batch.
How Sixtyfour AI Started
Sixtyfour started like most good ideas do—half out of frustration, half out of curiosity.
It was January. I was at Whatnot (YC W20), and Chris had just taken time off from school. We’d both built startups before, and we knew how painful customer discovery was. Identifying the right leads felt broken. So much of it relied on tedious, manual research.
We had a hunch: what if we could automate that grind?
On our very first call, one of our friends—a founder at a VC-backed startup—paid us to help them find individual psychiatrists in specific geographies. That’s when it clicked: tools like Apollo and ZoomInfo didn’t have solid data on niche, local businesses. Building those lead lists meant scraping directories and manually verifying info online.
So we hacked together a prototype that could run “deep research” on any business or person—pulling together everything publicly available.
It worked. Within weeks, we helped that customer generate ~$5,000 in new revenue, with only $300 in costs on our end. We weren’t making money yet, but the signal was clear: this was valuable.
From there, we started aiming higher—going after companies with larger deal sizes and more complex workflows. That’s where our product really shines.
Right around then, the YC interview email landed—midway through a customer call. Twelve hours later, Chris had flown in from Texas and was crashing on my floor in Berkeley. We walked out of the interview thinking we bombed it. Two days later, we were apartment-hunting in San Francisco, and I had submitted my resignation at Whatnot. We were in.
The Road Ahead
Now with YC behind us, we’re going all in on building the best AI sales research platform in the world.
It started with an enrichment API. Today, it’s become a full-blown research engine that can surface intel on nearly any person or business. We might be the only platform that can reliably identify tiny, obscure businesses—ones with just a couple employees in some corner of the world—and pull up real, actionable contact info. If it exists online, we can find it.
In the last two months alone, we’ve grown revenue 20x. But more importantly, we’re generating serious pipeline for our customers—and seeing even more value being built on top of our API.
And that’s just the beginning.
One use case we’re especially hyped about: finding every customer of legacy software companies. With vertical AI startups rapidly disrupting these niches, that data is turning out to be gold. If that’s something you’re working on, we’d love to talk.
Thank You
We wouldn’t be here without the early believers—our first customers, friends, and mentors who took a bet on us when all we had was a scrappy prototype and a strong conviction.
We’re still that same team, two founders who just wanted to build something useful - something people want and love. And we’re more excited than ever.
Thank you to everyone who’s been part of the journey so far. We’re just getting started.
Building something that needs better sales intelligence? We’d love to help—reach out here or DM me on Twitter.