What it does
Baby Tracker by Alder is an invite-only app that two caregivers use to log a baby's feeds, pumping, diapers, sleep, medication, growth and vaccines. It works offline and keeps both parents' phones in sync.
The problem
In the first months, two people share the care and both need the same answers at 3am: when was the last feed, which side, how long did the baby sleep, was the medicine given. Notes apps and group chats lose that detail, and most tracking apps are built for one user, full of ads, or need an account for every relative.
I wanted one shared record that is quick to update with one hand, works without signal, and is private by default.
How it works
Each family is a private space with two invited caregivers. Logging an event takes a couple of taps: pick the type, adjust the time if needed, save. The Summary screen shows the last event of each type and today's totals. The Timeline shows the whole day in order, so either parent can see at a glance what happened while they slept.
The app is a progressive web app, so it installs from the browser on iOS and Android without an app store. Entries are saved on the device first and sync through Supabase when there is a connection, so it keeps working offline. Growth and vaccine records sit alongside the daily log, ready for check-ups.