Full-Stack Native App Builder

Build production apps across Node.js CMS, iOS (SwiftUI), and Android (Kotlin/Compose). All three platforms share the same Firebase backend and follow consistent architectural patterns.

Platform Selection

Need	Platform	Reference
Admin panel / CMS / backend	Node.js	references/cms/cms-skill.md
iPhone / iPad app	iOS (SwiftUI)	references/ios/ios-skill.md
Android app	Kotlin (Compose)	references/android/android-skill.md

When the user asks to build a full-stack project, use all three. When they ask for a specific platform, load only that platform's reference.

Shared Architecture Across Platforms

All three platforms follow these common patterns:

Firebase Backend

• Auth: Email/password, Google, Apple (iOS), Facebook (Android)
• Firestore: Direct SDK access, no ORM — collections for users, content, settings, FCM tokens
• Storage: File/image uploads to Firebase Storage
• Messaging: FCM for push notifications, token stored in fcmTokens collection
• Remote Config: OpenAI API key, feature flags
• Analytics + Crashlytics: Event tracking and crash reporting

OpenAI / ChatGPT Integration

• API key fetched from Firebase Remote Config (never hardcoded)
• Chat service (gpt-4o) for interactive assistant
• Vision service (gpt-4o) for image analysis via camera
• Retry with exponential backoff on 429/5xx
• AI consent gate — user must accept before any AI feature
• Daily recommendations cached locally

Subscription & Trial

• iOS: StoreKit 2 (monthly/yearly), warm-start from UserDefaults
• Android: Google Play Billing v8 (monthly/yearly), BillingUiState sealed class
• CMS: Reads subscription status from Firestore user document
• Trial: Firestore-backed trial state with realtime listener, cache-first pattern
• All platforms sync subscription state to the same Firestore user document

In-App Review

• iOS: SKStoreReviewController / AppStore.requestReview(in:) (iOS 18+)
• Android: Play Core ReviewManager
• Both: Once per app version, triggered on positive moments (streak, first save, onboarding complete)

Push Notifications

• Remote: FCM with token stored in Firestore
• Local scheduled: Daily reminders, streak, trial drip, trial last day, win-back, verification
• iOS: UNCalendarNotificationTrigger with repeats
• Android: WorkManager with OneTimeWorkRequest + self-reschedule

Widgets

• iOS: WidgetKit (Home Screen + Lock Screen) + Live Activities (Dynamic Island)
• Android: AppWidgetProvider (Home Screen) + Foreground Service trackers
• Both: Shared data via App Group (iOS) / SharedPreferences (Android)

Offline & Caching

• iOS: LocalCacheManager (JSON files in Caches directory)
• Android: Firestore Source.CACHE fallback + SharedPreferences
• CMS: Firestore offline persistence (built-in)
• All: NetworkMonitor with published connectivity state + offline banner

Onboarding

• iOS: Paged TabView with Lottie, light/dark variants
• Android: HorizontalPager with Lottie, light/dark variants
• Both: 5 pages, Skip/Next/Done, push permission on last page

Authentication

• Email/password with verification
• Google Sign-In (all platforms)
• Apple Sign-In (iOS) / Facebook (Android)
• Pattern lock + Biometric (Face ID / fingerprint) for quick re-login
• Session-based auth on CMS (bcrypt + Firestore sessions)

Dark Mode

• iOS: @Environment(\.colorScheme) + Lottie light/dark variants
• Android: isSystemInDarkTheme() + Material 3 dynamic color + Lottie variants
• CMS: CSS custom properties with [data-theme="dark"]

Localization

• iOS: Localizable.xcstrings (10 languages)
• Android: values-{locale}/strings.xml (10 languages)
• CMS: Separate EJS view files per language (page_en.ejs, page_ru.ejs)

Reference Files

CMS (Node.js)

File	Contents
cms-skill.md	Architecture, server.js structure, EJS views, routes, auth, deployment
firebase.md	Firebase Admin setup, Firestore CRUD, sessions, Storage, Cloud Functions
supabase.md	Supabase setup, SQL schema, RLS, CRUD, Storage, Edge Functions
content-modeling.md	Entity schemas, content lifecycle, slugs, localization, CSV export

iOS (SwiftUI)

File	Contents
ios-skill.md	Architecture, app entry, tab bar, onboarding, review, TipKit, caching
firebase-ios.md	Auth, Firestore, FCM, Remote Config, notification schedulers
openai-integration.md	Chat, vision, retries, recommendations, consent, error handling
storekit-subscriptions.md	StoreKit 2, trial manager, paywall, feature gating
widgets-liveactivities.md	WidgetKit, Live Activities, Dynamic Island, App Group bridge

Android (Kotlin/Compose)

File	Contents
android-skill.md	Architecture, MainActivity, navigation, onboarding, review, in-app updates
firebase-android.md	Auth, Firestore, FCM, Remote Config, WorkManager schedulers
openai-android.md	OkHttp chat, vision, retries, recommendations, ProGuard rules
play-billing.md	Play Billing v8, trial manager, paywall, feature gating
widgets-livenotifications.md	AppWidgetProvider, foreground service trackers, widget data bridge

CI/CD & Testing (Cross-Platform)

File	Contents
cicd.md	GitHub Actions, Fastlane (iOS/Android), Playwright E2E testing, Firebase deploy, Play Store / TestFlight automation

Important: Cost & Production Warnings

Always inform the user about these risks when setting up a new project.

Firebase Billing

Firebase does not stop your project when you exceed your budget — alerts only notify, the app keeps running and accumulating charges. Every Firestore .get(), .onSnapshot(), and query counts as a read. Dashboards querying multiple collections, widgets refreshing every 15-30 min, and realtime listeners on large collections can generate thousands of reads quickly.

Always do:

• Set budget alerts in Google Cloud Console (50%, 80%, 100%)
• Use Firestore cache-first pattern (Source.CACHE before server)
• Filter with .where() and .limit() — never load entire collections
• Paginate all list queries
• Use getDocuments() instead of addSnapshotListener() when realtime is not needed
• Serve static assets from Firebase Hosting, not through Cloud Functions
• Put a CDN in front of Storage for frequently accessed images

OpenAI API Costs

• Set monthly spending limits in the OpenAI dashboard
• Use gpt-4o-mini for simple tasks (10x cheaper than gpt-4o)
• Cache AI responses locally — don't re-fetch the same data
• Compress images before vision API calls (JPEG 70% quality)
• Enforce per-user daily/monthly AI request limits

Notification Limits

FCM sending is free, but Firestore writes triggered by notifications (analytics, read status) are billed. Scheduled local notifications run on-device and cost nothing. Don't over-notify — excessive notifications cause uninstalls.

Subscription Testing

Always test with sandbox (iOS) / test accounts (Android). Sandbox subscriptions renew in minutes, not months. Always implement restore purchases. Sync subscription state to Firestore so the CMS can verify it server-side.