Authentication providers overview in Firebase - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Which Firebase Authentication provider supports signing in with a phone number?

Firebase offers several ways for users to sign in. Which provider allows users to sign in using their phone number?

A Email and Password

B Anonymous Authentication

C Google Sign-In

D Phone Authentication

💡 Hint

Think about which method uses SMS codes to verify users.

Phone Authentication uses SMS messages to verify the user's phone number and sign them in.

❓ service_behavior

intermediate

What happens when a user signs in anonymously in Firebase Authentication?

When a user signs in anonymously, what is the behavior of their authentication state?

A The user gets a temporary ID that can be linked to a permanent account later.

B The user must provide an email and password immediately.

C The user is permanently registered with Firebase without any further action.

D The user cannot access any Firebase services until they verify their phone number.

💡 Hint

Anonymous sign-in is often used to let users try the app before registering.

Anonymous Authentication creates a temporary user ID that can later be linked to a permanent account.

❓ security

advanced

Which Firebase Authentication provider requires OAuth 2.0 tokens for sign-in?

Among Firebase Authentication providers, which one uses OAuth 2.0 tokens to authenticate users?

A Email and Password Authentication

B Google Sign-In

C Custom Token Authentication

D Phone Authentication

💡 Hint

OAuth 2.0 is a common protocol used by major identity providers.

Google Sign-In uses OAuth 2.0 tokens to authenticate users securely.

❓ Architecture

advanced

How does Firebase Authentication handle multiple providers for a single user?

If a user signs in with Google and later with email/password, how does Firebase manage these identities?

A Firebase allows linking multiple providers to a single user account.

B Firebase merges the accounts automatically without user action.

C Firebase creates separate user accounts for each provider.

D Firebase deletes the old account when a new provider is used.

💡 Hint

Think about how users can sign in with different methods but keep the same profile.

Firebase supports linking multiple authentication providers to one user account to unify identities.

✅ Best Practice

expert

Which Firebase Authentication provider is best suited for apps requiring no user credentials and temporary sessions?

For an app that wants users to try features without signing up or providing credentials, which Firebase Authentication provider is most appropriate?

A Email and Password Authentication

B Google Sign-In

C Anonymous Authentication

D Phone Authentication

💡 Hint

Consider which provider creates temporary user sessions without requiring sign-up.

Anonymous Authentication allows users to use the app temporarily without credentials, ideal for trials.