How we built a fertility app that reached 300,000 registered users
Yesmom was a femtech startup in Bangkok, built around giving women clear insight into their reproductive health. Between 2018 and 2021 we built its cycle tracking and fertility app from a blank slate: planning, architecture and infrastructure included. It ran on one Flutter codebase across iOS and Android, and reached 300,000 registered users before the company closed during COVID in 2021.
300K
Registered users
3
Years in production
- Mobile App Development
- Product Architecture
- Custom UI Engineering
- Backend Infrastructure
- Flutter
- Dart
- Firebase
- Firebase Authentication
The Challenge
Fertility data is some of the most sensitive information a health app can hold, and Yesmom wanted a product that felt nothing like a dashboard. It had to track cycles, ovulation windows and pregnancy probability, carry daily symptom and mood logging alongside calendar and prediction views, and put a circular cycle tracker at the centre of the interaction. No off-the-shelf component existed for that pattern. There was no existing codebase either. We started from a blank slate.
Our Approach
We built the app from scratch, planning, infrastructure and architecture included. The circular selector on the calendar screen is a custom component, not a library pull. We drew the vector elements and wrote the gesture handling ourselves, so a user could scrub through cycle days with one thumb and watch the fertility window, cycle day and pregnancy chance update as they moved. Around it we shipped an ovulation calendar with period and cycle day marking, a cycle dashboard, a daily log covering lifestyle, physical symptoms and mood, and insights built on that logged data. Flutter gave one codebase across iOS and Android. Firebase carried the backend, auth and storage. A small team could keep shipping without a platform team behind them.
The Result
The app ran for three years and reached 300,000 registered users. In 2021 COVID closed the business and the app came down with it. That does not change what the engineering did while it ran: a Flutter and Firebase build, made by a small team, carried 300,000 accounts and an interface drawn from scratch because nothing off the shelf fitted. That is the part that transfers.
Want a build like this one?
Same team, same senior engineers. Tell us what you are building and we will tell you how we would approach it.
