Phone number authentication in Firebase - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is phone number authentication in Firebase?

Phone number authentication is a method that lets users sign in to an app using their phone number. Firebase sends a code via SMS to verify the user’s identity.

beginner

Why is phone number authentication useful?

It allows users to sign in without remembering passwords. It uses something they have (their phone) to verify identity, making it simple and secure.

beginner

What is the role of the verification code in phone number authentication?

The verification code is sent by Firebase via SMS to the user’s phone. The user enters this code in the app to prove they own the phone number.

intermediate

What is reCAPTCHA in Firebase phone authentication?

reCAPTCHA helps prevent abuse by bots. Firebase uses it silently or visibly to make sure the phone number verification is done by a real person.

intermediate

What happens if the verification SMS is not received?

Firebase allows resending the code after a short wait. Users can also use the auto-retrieval feature on supported devices to verify automatically.

What does Firebase send to verify a phone number?

A A push notification

B An email with a link

C A phone call with a password

D A verification code via SMS

Firebase sends a verification code via SMS to confirm the phone number.

What is the main purpose of reCAPTCHA in phone authentication?

A To prevent automated abuse by bots

B To verify the phone number format

C To send the SMS faster

D To store user data securely

reCAPTCHA helps prevent abuse by ensuring a real person is verifying the phone number.

Which of these is NOT a step in Firebase phone authentication?

A Firebase sends verification code

B User enters password

C User enters phone number

D User enters verification code

Phone authentication does not require a password; it uses a verification code instead.

What can a user do if they don’t receive the verification SMS?

A Wait and request to resend the code

B Change their email address

C Restart the app without entering phone number

D Use a password instead

Users can wait and request Firebase to resend the verification code.

What does Firebase use to automatically verify the code on some devices?

A Manual code entry only

B Email confirmation

C Auto-retrieval feature

D Voice call verification

Firebase can automatically detect the verification code on supported devices using auto-retrieval.

Explain how Firebase phone number authentication works from start to finish.

Think about the steps a user takes and what Firebase does behind the scenes.

Describe the security measures Firebase uses to protect phone number authentication.

Consider how Firebase ensures only real users can verify their phone numbers.