The Idea:
In June 2026, Zach Yadegari walked out of MyFitnessPal at 19 with an exit most founders spend a career chasing. Months earlier, the calorie-tracking giant had bought Cal AI, the snap-a-photo calorie app he’d built in high school with his friend Henry Langmack.
He could have coasted. Instead, he went straight to work on a bigger bet, one that cut against the very thing that made him rich.
Yadegari had become convinced that apps were on borrowed time. Uber, DoorDash, your inbox, your shopping apps: all of it, he believed, would collapse into a single AI assistant that just does things for you.
The catch was trust. Amazon had already bought Bee, a wearable that records everything you say. Yadegari wanted the opposite: an assistant you text over iMessage, that sits on your wrist, never listens unless you tap it, never sees your card details, and never sells your conversations to advertisers.
This was the beginning of Persona.
The Execution:
- Ninth grade: After schools handed out Chromebooks and blocked game sites, Yadegari built an unblocked-games site and named it “Totally Science” so it wouldn’t get blocked too. He sold it for $100K at 16.
- May 2024: Still in high school, he launched Cal AI with Langmack and Blake Anderson. Within eight months it had 5M+ downloads and was doing over $2M in monthly revenue, he said.
- April 2025: Despite a 4.0 GPA and a multimillion-dollar company, he was rejected by 15 of 18 top colleges. The post went viral on X.
- Spring 2025: MyFitnessPal CEO Mike Fisher, who tracks some 70 competitors, spotted Cal AI climbing the charts. Talks ran on and off for almost a year.
- December 2025: The deal closed. By then Cal AI had passed 15M downloads and $30M+ in annual revenue in under two years, run by a team of just seven. Terms weren’t disclosed.
- June 2026: Yadegari left MyFitnessPal and started Persona with a co-founder who’s yet to be named.
- Summer 2026: Persona launched as a free iMessage beta, picking up a few thousand users and five figures in preorders for a $179 wearable band before it had shipped.
- October 5, 2026: The category got crowded fast. Days before Persona’s announcement, another 19-year-old raised $11M for Ghost, a $3,499 personal AI computer.
- October 8, 2026: Persona raised $10M led by Vine Ventures, with Z Fellows founder Cory Levy and Collective Global joining.
- Today: The band ships in December, with ads shown during shopping research as the business model. Yadegari speaks at TechCrunch Disrupt next week on creating viral growth.
The lesson?
Yadegari made his money on a single-purpose app. Then he raised $10M betting that single-purpose apps are dying, Cal AI included. Most founders spend their second act building a bigger version of their first hit, protecting the thing that worked. The sharper move is asking what kills your last company, and building that. The best second act doesn’t defend your first one. It bets against it.