rex.fit
YC W23Entrepreneur First '23San Francisco, US · Founded 2023 · 2 employees · 9 known investors
Rex.Fit makes a wearable camera device that uses computer vision to automatically track food intake and nutrition, alongside an API that fitness facilities integrate for nutritional analysis.
Also known as Babylon AI · BabylonAI · Rex · BabylonAI Inc. · Rex Nutribot · Rex.Fit
Founders & leadership· Y Combinator alumni (W23)
rex.fit was founded in 2023 by Ahmad Roumie and Rangel Milushev.
Investors · 9
Also in the syndicate · 7
Company profile
researched Aug 2026Rex.fit builds AI-based nutrition and fitness tracking products. Its flagship hardware product, The Drop, is a wearable AI pendant with an onboard smart AI chip that uses computer vision to detect when the wearer is eating; when food is classified, an LED indicator activates and the device records the meal, after which a cropped image is uploaded to the cloud and analyzed into calories, protein, carbs and fats that appear in the companion mobile app. The company describes it as a fully automated nutrition tracker intended to remove manual logging entirely.
Alongside the device, Rex.fit operates a conversational AI coach on WhatsApp (originally launched as Rex Nutribot). Users log meals by sending a photo or a text description, log workouts in the same thread, request tailored workout suggestions, and receive daily reports with feedback on diet and lifestyle. The product also includes an AI body scanner that generates body metrics as an alternative to BMI. A separate web app presents gamified workouts in which AI recognizes user movements and provides instant feedback.
The underlying nutrition estimation and recommendation technology is also offered as an API integrated by fitness chains, according to Y Combinator's company profile.
Founding story
According to the company's launch post, co-founders Rangel Milushev and Ahmad Roumie met at Entrepreneur First in Paris in 2022 and have worked together since. Ahmad Roumie is described as a computer vision engineer with a Masters in Robotics from ETH Zurich who previously worked on autonomous retail stores and autonomous robots (legged, UAV and crawler); Rangel Milushev is described as an AI engineer with a B.A. in Computer Science from Harvard. They first launched Rex Nutribot on WhatsApp in December 2023, and after concluding from more than 20,000 users that existing tools required too much manual input, developed The Drop wearable.
Business model
Rex.fit sells a consumer hardware device (The Drop, priced from USD 199 and initially distributed via Kickstarter pre-orders) together with a companion app, and operates a conversational AI coach delivered through WhatsApp. In parallel, the company licenses its nutrition estimation and recommendation technology as an API to fitness chains; YC states this API business generates hundreds of thousands of dollars in yearly revenue for those chains.
Hardware sales of The Drop (from USD 199, sold initially as Kickstarter pre-orders), a consumer AI coaching service accessed through WhatsApp, and API licensing of nutrition estimation and recommendation technology to fitness chains.
Traction
More than 93,000 USD in pre-orders (~450 units) for The Drop reported shortly after its launch; more than 20,000 users of the WhatsApp Nutribot service; the nutrition API is described as integrated by fitness chains and generating hundreds of thousands of dollars in yearly revenue for them. Team size is listed as 2.
Latest developments
The most recent documented developments are the December 2024 Kickstarter launch of The Drop, with more than USD 93k in pre-orders across roughly 450 units reported shortly after launch, and December 2024 press coverage by Fox News. Devices for early adopters and beta testers were stated to ship in the summer following launch. Y Combinator continues to list the company as Active with a team size of 2 and no open roles posted.
▸Full profile — market position, technology, go-to-market, geography, history, risks & controversies
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.
Compiled by commissioned research from 8 cited public sources — announcements, filings, and press listed under research sources below.
Key figures
latest reportedCompany-reported or press-reported figures, each dated to when it was claimed — not independently audited.
Competitors · 2
by search overlap
Companies competing with rex.fit for the same Google search keywords, organic and paid, via search-intersection analysis.
Timeline · 5
launches, deals, and filingsFox News article: 'Food tracking just got lazy — in the best way possible — with this wearable'.
Kickstarter launch of The Drop, a wearable AI pendant with an on-device smart AI chip that detects eating, records the meal and sends a cropped image to the cloud for breakdown into calories, protein, carbs and fats. Pricing starts at USD 199 in three colors (carbon black, metallic blue, gold), with early adopter and beta tester deliveries planned for the summer.
Launched a WhatsApp-based calorie tracking assistant that logs meals from a photo or text message; the company reports it later exceeded 20,000 users.
Company launch post presenting Rex.fit as an AI workout and nutrition coach.
Launch of Babylog, a lightweight open-source logging library for logging image and prediction data from edge devices.
Dated company events from announcements, filings, and press; legal rows summarize public dockets and regulator releases.
In the news
▸Research sources · 8
primary sources listed
- rex.fitrex.fit · web
8 public sources were cited for this profile; the first-party ones are listed here.
Frequently asked questions
- What does rex.fit do?
- Rex.fit builds The Drop, a wearable AI camera pendant and app that automatically tracks meals and nutrition via computer vision.
- Who founded rex.fit?
- rex.fit was founded by Ahmad Roumie, Rangel Milushev in 2023.
- Who are rex.fit's investors?
- rex.fit's investors include Entrepreneur First, Y Combinator.
- Where is rex.fit headquartered?
- rex.fit is headquartered in San Francisco, US.