20 · App development · Fitness
MaxxLevel: a fitness app for kids that never nags.
MaxxLevel is a private project: René Mattis designed and developed the app together with his son. Kids set up a weekly plan, tick things off every day and see their progress – no reminders about misses, no red days, no account and no server.
Private project by René Mattis, developed together with his son
- Native iOS app
- SwiftUI
- SwiftData
- CloudKit
- WidgetKit
- Swift Charts
- No account
- No server
- no account, no tracking – data stays on the device and in the private iCloud space
- 16 exercises
- preinstalled, add your own with unit, category and icon
- At most 2
- notifications a day – never about missed days or streaks at risk
01 · Idea
Many fitness apps work with pressure: red days, reminders, broken streaks, leaderboards. For kids, that is the wrong approach. MaxxLevel was meant to show what is due and what has been done – never what was missed – and to work without an account, without its own server and without tracking.
02 · Solution
A native SwiftUI app for iPhone and iPad. Training: for each weekday, set which exercise is due and how often, from templates such as “Beginner” or with a short assistant. “Today” shows a progress ring and one card per exercise to tick off, set by set; two out of three sets count too. The plan grows in small steps.
Seeing progress: the streak counts the days in a row, and one joker per week quietly covers a missed day. History of the last 16 weeks, insights per weekday, records and badges that are never taken away.
Crew: celebrate progress together with friends and pursue a shared goal – no leaderboard, no chat, only icons to cheer each other on. Before joining for the first time, a parent step asks for consent.
Reminding without pressure: in the morning what is due, after the last set some praise, on Sundays the weekly review. Ticking off also works from the notification, the widget or via Siri.
See all screens in the app references →
03 · Result
A fitness app that motivates instead of nagging. Everything stays on the device and syncs via the private iCloud space; the app also works entirely without iCloud, can be backed up to a file and, if wanted, adds completed days to Apple Health. When the plan changes, the history stays the same – it stores what actually applied on that day.
04 · Workflow
- On the device: No account, no server, no tracking, Sync via private iCloud, Widgets · Siri · Apple Health, Backup to a file
- A DAY WITH MAXXLEVEL: Weekly plan (exercises per weekday) → Morning (notification: what is due today) → Today (tick off set by set) → Streak & joker (one joker per week covers a day) → Sunday (weekly review, never nagging)
- CREW: Crew (with parental consent) → Shared goal (e.g. 1,000 push-ups together)
05 · Insights
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