No Sugar Challenge
Health app refactoring: legacy to SwiftUI with event-driven architecture and cloud sync
Screenshots
Client
Health startup with an existing iOS app in the App Store. The app needed a complete rebuild and expansion with new features.
Problem
The app had a basic architecture that could not scale. Needed: full data model migration to event-driven architecture with Firestore sync, new personalized onboarding with scoring system, redesigned home screen with daily tasks and insights, complex timer logic with streak tracking and pause mode, subscription management via Superwall.
Solution
Full rewrite to SwiftUI with MVVM. Migrated data architecture from monolithic JSON to event-driven model with Firestore offline-first sync and iCloud backup. Built personalized onboarding: 4 question groups with parameter calculation and scoring, dynamic blockers, personal daily tasks. Improved existing AI food scanner. Redesigned home screen with challenge timer, daily tasks, and insight system (1 per day). Complex timer service with streak calculation, pause mode (freeze without breaking streak), auto-backfill for missed days. Firebase Remote Config as single source of truth for all business logic and content. StoreKit 2 + Superwall subscriptions. Improved Amplitude + Firebase analytics.
Results
- +Live in App Store with growing user base
- +Event-driven architecture with cloud sync
- +Personalized onboarding with scoring system
- +Daily tasks and insights system
- +Subscription model with multiple tiers via StoreKit 2
- +73 tests covering key timer logic
Role & timeline
Lead iOS Developer. Full architecture refactoring, data migration, timer system, subscriptions. January 2025 - March 2026