Email/password signup in Firebase - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ service_behavior

intermediate

What happens after a successful email/password signup in Firebase?

When a user signs up with email and password using Firebase Authentication, what is the immediate state of the user session?

Firebase

firebase.auth().createUserWithEmailAndPassword(email, password).then(userCredential => {
  // What is true here?
});

A The user session is created but remains inactive until email verification.

B The user is automatically signed in and the session is active.

C The user must manually sign in after signup to activate the session.

D The user is signed out immediately after signup for security reasons.

💡 Hint

Think about what Firebase does by default after creating a user.

Firebase automatically signs in the user after a successful email/password signup, so the session is active immediately.

❓ security

intermediate

Which Firebase rule prevents users from reading other users' data?

Given Cloud Firestore with user data stored under /users/{userId}, which security rule ensures users can only read their own data?

Firebase

rules_version = '2';
service cloud.firestore {
  match /databases/{database}/documents {
    match /users/{userId} {
      allow read: if request.auth.uid == userId;
    }
  }
}

A request.auth.uid == userId

B request.auth.email_verified == true

C request.auth.uid != userId

D true

💡 Hint

Users should only access data where their ID matches the data path.

The rule request.auth.uid == userId restricts read access to only the authenticated user's own data.

❓ Configuration

advanced

What is the correct Firebase config snippet to enable email/password signup?

Which Firebase Authentication configuration snippet correctly enables email/password signup in the Firebase console?

A Set <code>allowEmailPasswordSignup: true</code> in firebase.json file.

B Add email and password fields in Firestore database rules.

C Enable 'Email/Password' provider in Authentication > Sign-in method tab.

D Create a Cloud Function to handle email/password signup manually.

💡 Hint

Think about the Firebase console settings for authentication.

Enabling the 'Email/Password' provider in the Authentication sign-in method tab activates this signup method.

🧠 Conceptual

advanced

Why is email verification important after signup?

After a user signs up with email and password, why should you require email verification before granting full access?

A To allow users to sign in without a password.

B To automatically reset the user's password.

C To speed up the signup process.

D To confirm the user owns the email and prevent fake accounts.

💡 Hint

Think about security and trust in user identity.

Email verification confirms the user controls the email address, reducing fake or malicious accounts.

✅ Best Practice

expert

What is the best practice for handling errors during email/password signup?

When a signup attempt fails (e.g., weak password, email already in use), what is the best way to handle errors in your app?

Firebase

firebase.auth().createUserWithEmailAndPassword(email, password).catch(error => {
  // What should you do here?
});

A Show a clear, user-friendly message explaining the error cause.

B Log the error silently and do not inform the user.

C Reload the page automatically without explanation.

D Ignore the error and proceed as if signup succeeded.

💡 Hint

Good user experience includes clear communication.

Displaying clear messages helps users understand and fix signup issues, improving experience and reducing frustration.