The brief was a social, real-time game that could scale and make money without standing up a dedicated game cluster on day one.
Firestore listeners drive the UI. Cloud Functions own scoring and the rules that must not live on the client. SwiftUI covers the screens. Auth and security rules gate rooms. RevenueCat and AdMob handle subscriptions and ads. The product is also localized.
Consistency across many clients, reconnects, and brief offline stretches is the actual engineering. The result is a multiplayer loop with a revenue path.