firebase

Firebase Skill

Firebase/Firestore patterns for web and mobile applications with real-time data, offline support, and security rules.

Sources: Firebase Docs | Firestore Best Practices | Security Rules

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Core Principle

Denormalize with purpose, secure with rules, scale horizontally.

Firestore is a document database - embrace denormalization for read efficiency. Security rules are your server-side validation. Design for your access patterns.

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Firebase Stack

Service	Purpose
Firestore	NoSQL document database with real-time sync
Authentication	User auth, OAuth, anonymous sessions
Storage	File uploads with security rules
Functions	Serverless backend (Node.js)
Hosting	Static site + CDN
Extensions	Pre-built solutions (Stripe, Algolia, etc.)

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Project Setup

Install Firebase CLI

# Install globally
npm install -g firebase-tools

# Login
firebase login

# Initialize in project
firebase init

Initialize with Emulators

firebase init emulators

# Start local development
firebase emulators:start

Project Structure

project/
├── firebase.json           # Firebase config
├── firestore.rules         # Security rules
├── firestore.indexes.json  # Composite indexes
├── storage.rules           # Storage security rules
└── functions/              # Cloud Functions
    ├── src/
    ├── package.json
    └── tsconfig.json

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Firestore Data Modeling

Document Structure

// Good: Flat documents with all needed data
interface Post {
  id: string;
  title: string;
  content: string;
  authorId: string;
  authorName: string;      // Denormalized for display
  authorAvatar: string;    // Denormalized
  tags: string[];
  likeCount: number;       // Aggregated counter
  createdAt: Timestamp;
  updatedAt: Timestamp;
}

// Collection: posts/{postId}