Cal AI's 19-Year-Old Founder Raises $10M for AI Wearable Startup Persona

Zach Yadegari, the 19-year-old co-founder of calorie-tracking app Cal AI, has raised $10 million for his new AI agent startup, Persona. Vine Ventures led the round, with Z Fellows founder Cory Levy and Collective Global participating.

The raise comes months after a headline exit. In March, MyFitnessPal acquired Cal AI for an undisclosed sum after the upstart overtook the older app in the app store rankings. MyFitnessPal told TechCrunch the founders decided to sell after Cal AI pulled in more than $30 million in annual revenue in under two years.

Yadegari and his co-founders initially stayed on at MyFitnessPal and kept developing Cal AI. He left in June, he tells TechCrunch, and moved straight to his next venture. He is building Persona with an unnamed co-founder.

What is Persona?

Persona is a personal AI assistant in the vein of Instinct or Meta's Muse, but with a hardware component: a $179 wearable band expected to ship in December. An app is also in the works.

The closest comparison is Bee, the wearable AI device Amazon acquired in 2025. Persona's band differs in one key respect, Yadegari says: it will not run ambient AI. The device won't always listen and record. A button activates the assistant, or users can configure it to wake with a flick of the wrist.

How does Persona handle privacy?

Privacy is the design centerpiece. Persona does not run its AI model or store user data on the device. The model runs in Persona's cloud, with data encrypted in transit and at rest. Users can delete their data, the company says, and conversations cannot be sold to advertisers or data brokers.

The team is also building defenses against phishing and prompt-injection attacks — two weak spots that AI labs like OpenAI say plague agents, Yadegari notes.

Payments carry additional guardrails. The agent cannot see a user's credit-card details, purchases require user approval, and payments run through external providers such as Stripe Link, Stripe's secure wallet built for agents.

Can an ad-funded assistant stay unbiased?

Persona's business model relies on ads, even though user data stays off the market. Yadegari says the company will show advertised products during shopping research. He argues recommendations remain unbiased because, in his telling, "the agent knows their preferences" — referring to users — and surfaces matching items, some of them sponsored, without knowing which are advertised.

Persona has launched as a free beta in which users interact with the assistant via iMessage. It has attracted "a few thousand beta users," Yadegari said. The band has already generated "five figures in preorder revenue." Like other consumer AI assistants, Persona can order food or rides, take notes, book travel, and answer questions and emails.

Yadegari frames the bet as a consolidation play. "All of the utility apps that you use on your phone day-to-day, whether those are apps for shopping, whether it's Uber, DoorDash, your email — these are all collapsing and will collapse into a single super app powered by an AI assistant," he said.

His longer-term goal is proactivity: "It can offer help and solve problems before you even know you have a problem, and overall be more seamless with your life, so that you don't need to stare at a rectangle in your hand all day."

Yadegari is no stranger to early wins. Before Cal AI, he built his first business in the ninth grade and sold it for $100,000 at 16. He is scheduled to speak at TechCrunch Disrupt, October 13-15 at the Moscone Center in San Francisco. Persona's December band launch will test whether a privacy-first, button-activated assistant can carve out space against Meta and Amazon in the wearable AI market.