Why we made coparenting first-class
In most music-practice apps, the family-management model is simple: one adult creates the account, one adult adds the children, one adult sees the data. If a second adult wants in, they either share login credentials (terrible from a security and audit perspective) or they don’t see the data at all.
That model doesn’t match what we see in real households. Music practice in our family, and in most families we know , is a shared concern. Sometimes my wife is the one driving the kid to lessons; sometimes I am. Sometimes the kid does practice while one of us is at work; sometimes when we’re both home. In separated households, both parents often share the music life even when the rest of life is divided. None of those situations are well served by a one-account-per-family model.
So coparent sync is built into My Crescender Family from the data model up, not bolted on as an afterthought.
How it works
The first adult creates the family. From their Settings → Coparents screen they invite the second adult by email. The invitation arrives as a magic link; clicking it on the second adult’s device walks them through creating their own account and accepting the share.
Once accepted, both adults are equal owners of the family. Both see the same children, the same goals, the same calendar, the same practice history. Either adult can:
- Add or retire a child.
- Adjust a daily practice goal.
- Add, edit, or delete calendar events.
- Generate a kid-mode unlock code on their own device.
- Change notification preferences.
- Trigger a data export (delivered to whoever requested it).
The only thing each adult can do independently is set their own avatar, their own display name, and their own notification preferences. Family-level data is fully shared.
What gets synced (and when)
Every change either adult makes, every practice session the kid logs, every event you add, propagates to the other adult’s device usually within a few seconds. The sync engine runs on three triggers: when the app comes to the foreground, when you pull-to-refresh, and when a real-time channel notifies us that there’s new data for your family.
When a device is offline, changes queue locally in a SQLite database (we use WatermelonDB under the hood). The instant the device comes back online, the queue drains and the other adult sees the changes in their next refresh tick. We designed this assuming bad connectivity is the norm, not the exception, your kid practices in a lot of places that have flaky WiFi.
Notifications across both adults
When a kid finishes a practice session, both adults get the opt-in push notification (assuming both have opted in). The notification carries the kid’s name, the instrument, and the duration, useful when one parent is supervising and the other isn’t home.
Event reminders fire on both phones at the same time. If you tap one to mark it “heading there now”, that state syncs to your coparent’s view of the event so they don’t have to ask.
Separated households
The two adults don’t have to live together. If you and your coparent are separated, you can both run My Crescender Family from your own households, both have your own kid-mode unlock codes, and both see the practice your kid does at either house.
We don’t encode the relationship between the adults in the app, we don’t care whether you’re married, divorced, separated, a step-parent, or a grandparent who shares custody. The data model just knows that both of you are adults attached to the same family. That’s the right level of abstraction.
If the relationship between the adults changes, either of you can remove the other from the family at any time, from Settings → Coparents. The removed adult loses access immediately; they keep their own Crescender account but can’t see this family any more.
Why we don’t cap the number of adults
The data model supports any number of adults attached to a family, not just two. In practice families add a third (a grandparent who runs the after-school routine, a long-term au pair, an aunt who’s the family’s music advisor) often enough that we didn’t want to enforce a hard cap.
The UI is optimised for two-adult households because that’s the most common case, but invite a third or fourth from the same Settings screen and it all works.