firebase-auth-basics

From README

Prerequisites Firebase Project: Created via npx -y firebase-tools@latest projects:create (see firebase-basics). Firebase CLI: Installed and logged in (see firebase-basics). Core Concepts Firebase Authentication provides backend services, easy-to-use SDKs, and ready-made UI libraries to authenticate users to your app. Users A user is an entity that can sign in to your app. Each user is identified by a unique ID (uid) which is guaranteed to be unique across all providers. User properties include: uid: Unique identifier. email: User's email address (if available). displayName: User's display name (if available). photoURL: URL to user's photo (if available). emailVerified: Boolean indicating if the email is verified. Identity Providers Firebase Auth supports multiple ways to sign in: Email/Password: Basic email and password authentication. Federated Identity Providers: Google, Facebook, Twitter, GitHub, Microsoft, Apple, etc. Phone Number: SMS-based authentication.