rex.fit

Market position

Y Combinator classifies the company under artificial intelligence, hard tech, computer vision, consumer health services and fitness. It is an early-stage, two-person team operating in automated nutrition tracking, with user testimonials on its site explicitly comparing the product favorably to MyFitnessPal.

The company positions The Drop as the first fully automated nutrition tracker, contrasting it with existing nutrition apps that require substantial manual input; the founders state that prior solutions, including their own WhatsApp bot, still depended on user effort and failed to build a durable tracking habit. Other stated differentiators are the passive wearable form factor, a chat-based interface intended to feel like texting a friend, combined nutrition and workout logging in a single conversation, an AI body scanner as an alternative to BMI, and backing from Y Combinator and Entrepreneur First.

Technology

Computer vision and AI models running partly on a smart chip embedded in the wearable, which classifies whether the user is eating and triggers recording; images are cropped and sent to cloud algorithms that estimate calories, protein, carbs and fats. Additional components include image- and text-based meal logging through a chat interface, an AI body scanner producing body metrics, AI movement recognition for gamified workouts, and Babylog, an open-source library for logging image and prediction data from edge devices.

Go-to-market

Direct-to-consumer via the rex.fit website (pre-orders and a WhatsApp entry point), a Kickstarter crowdfunding campaign for The Drop, a bi-weekly email newsletter, free web tools (AI meal planner, TDEE calculator, BMI calculator, food diary template) used as acquisition channels, and a B2B API channel selling nutrition analysis to fitness chains.

Health- and fitness-focused consumers seeking to lose weight, build muscle or improve longevity, plus fitness chains that integrate the company's nutrition analysis API.

Geography

Y Combinator lists the company's location as San Francisco. Third-party directories give conflicting locations: one lists Zürich, Switzerland, another lists Dover, Delaware, USA. The WhatsApp-based service is delivered remotely and the Kickstarter campaign targeted international backers.

History

The company was founded in 2023 (a third-party profile dates the founding partnership to 2022, when the founders met at Entrepreneur First in Paris) and participated in Y Combinator's Winter 2023 batch. An open-source computer vision logging library, Babylog, was released in January 2023, followed by the Rex.fit AI workout and nutrition coach in September 2023 and the Rex Nutribot WhatsApp service in December 2023. In December 2024 the company launched The Drop wearable on Kickstarter, which was covered by Fox News later that month. The corporate entity behind the website is BabylonAI Inc.

Risks & controversies

Sources contain conflicting basic facts, including headquarters (San Francisco vs. Zürich vs. Dover, Delaware) and founding date (2023 vs. a 2022 founding date in one aggregator profile), and one aggregator's founder list omits the CEO. Funding figures and investor lists appear only in a single third-party aggregator and are not corroborated elsewhere in the material. Product risks implied by the sources include delivery of Kickstarter pre-orders (roughly 450 units) by a two-person team and dependence on cloud-based image analysis of meals, which involves continuous wearable camera capture and associated privacy considerations. A separate iOS app named 'Rex.life'/'Rex.Fit' published by Shenzhen United Power Technology Co., Ltd. exists in the App Store and is a distinct product from this company.