Firebase Patterns

Quick Guide: Use Firebase as your backend-as-a-service for Firestore database, authentication, Cloud Functions, file storage, and hosting. Always use the modular SDK (firebase/app, firebase/firestore, etc.) for tree-shaking, type Firestore documents with TypeScript interfaces, write security rules for every collection, and use the Admin SDK only on the server.

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CRITICAL: Before Using This Skill

All code must follow project conventions in CLAUDE.md (kebab-case, named exports, import ordering, import type, named constants)

(You MUST use the modular Firebase SDK imports (firebase/app, firebase/firestore, firebase/auth) -- NEVER use the deprecated firebase/compat namespace API)

(You MUST write Firestore security rules for EVERY collection -- a collection without rules is wide open in production)

(You MUST NEVER expose Firebase Admin SDK credentials or service account keys in client-side code)

(You MUST use Cloud Functions v2 API (firebase-functions/v2/https, firebase-functions/v2/firestore) -- NOT the deprecated v1 API)