Zach Yadegari

Zach Yadegari is an American teenage app founder best known as the co-founder and CEO of Cal AI, the AI calorie-tracking app that lets people log a meal by photographing their plate. Launched in May 2024 from the family home in Roslyn, New York, while Yadegari was still in high school, Cal AI passed $30 million in annual revenue within about two years and was acquired by MyFitnessPal in March 2026.

Yadegari started programming at around seven, mostly to make video games, and met future co-founder Henry Langmack at a coding camp at age 10. The two kept releasing apps, from games sites to a motivational alarm clock, planning to double down on whichever one took off. In ninth grade Yadegari built Totally Science, an unblocked-games website disguised as a science site so school filters would not catch it. Promoted through Yadegari's own TikToks, it grew to millions of users, and at 16 Yadegari sold it to the gaming company FreezeNova for $100,000.

Cal AI came next, co-founded with high-school friend Henry Langmack, with app maker Blake Anderson as a co-founder and Jake Castillo running influencer marketing. The app uses models from OpenAI and Anthropic to estimate calories from a photo. The team grew it almost entirely through paid and organic influencer content rather than app-store ads, pricing it low (around $30 a year) to maximise sign-ups. By March 2025 it reported more than 5 million downloads in eight months, and by the time of the sale it had passed 15 million downloads.

In April 2025 Yadegari went viral after posting that, despite a 4.0 GPA and a business on track for $30 million a year, 15 of the 18 top universities Yadegari applied to had rejected the application. MyFitnessPal announced the acquisition of Cal AI on March 2, 2026, citing more than $40 million in sales over the previous 12 months; terms were not disclosed. Yadegari stayed on briefly and left MyFitnessPal in June 2026.

In October 2026 Yadegari announced Persona, a personal AI assistant that works over iMessage and pairs with a $179 wearable band, and raised a $10 million round led by Vine Ventures. Yadegari is on Forbes' 30 Under 30 and has become one of the best-known examples of the young, TikTok-driven consumer app founders building on top of large language models.