Firebase Complete Guide 🔥

1. What is Firebase?

Firebase is a Backend-as-a-Service (BaaS) by Google used for authentication, database, hosting, and real-time apps.

2. Features

- Authentication (Login/Signup)
- Firestore Database
- Realtime Database
- Hosting
- Cloud Functions
- Storage (files/images)

3. Authentication

Supports:
- Email/Password
- Google Login
- Phone OTP

4. Firebase Web Setup

import { initializeApp } from "firebase/app";

const firebaseConfig = {
  apiKey: "YOUR_KEY",
  authDomain: "YOUR_PROJECT.firebaseapp.com",
  projectId: "YOUR_PROJECT"
};

const app = initializeApp(firebaseConfig);

5. Firestore Database

import { getFirestore, addDoc, collection } from "firebase/firestore";

const db = getFirestore(app);

await addDoc(collection(db, "users"), {
  name: "Sasank",
  role: "Developer"
});

6. Realtime Database

- Live data sync
- Chat apps
- Live notifications

7. Firebase Hosting

Commands:
npm install -g firebase-tools
firebase login
firebase init
firebase deploy

8. Storage

Used for:
- Images
- Videos
- Files

9. Real Use Cases

• Chat apps 💬
• Login systems 🔐
• Social media apps 📱
• Admin dashboards 📊

10. Mini Project Idea

Build a:
- Login + Signup system
- Save user data in Firestore
- Show realtime updates