Why is user being logged out from app using Firebase/auth?

Unexpected user logout is a very common and frustrating problem while using Firebase Authentication. In this comprehensive guide we will guide you with the important steps that will definitely help you in solving the problem. Let’s start.

Session Expiry & Token Issues

How Firebase Session Length Affects Auto-Logout and How to configure it?

• ID Token Lifetime:- Whenever the user sign-in, Firebase provides a short lived ID token (JWT). This token is valid for only one hour.
  

• Refresh Tokens:- With the ID tokens, a long refreshed token is also offered. These refresh tokens enable client SDK automatically to get new ID tokens without user intervention.
  

• Session Persistence:- By default, Firebase manages session persistence automatically and keeps logged in until a new token is provided.

To Configure it follow the below steps

• Web Apps:- You can configure long session persistence by setting auth persistence mode. Refresh token is only invalidated if the user is deleted, disabled or a major account change happens.
  

• Session Cookies:- For more control, Firebase admin SDK enables the users to create session cookies with custom expiration times.

Why Firebase Tokens Expire and how Silent Refresh Works?

• Security:- ID tokens expire after an hour. This expiration helps in minimizing the chance of stealing tokens.  This makes sure that even if a token is compromised, it has a limited window of validity.
  

• Silent Refresh:- The Firebase client SDK automatically uses the refresh tokens to gain new ID tokens before the old one expires.
  

• When Refresh Fails:- If the refresh tokens are canceled, the user must be logged out and sign in again.

Understanding onIDTokenChanged and its Role in Session Management

• Token Change Listener:- The onIDTokenChanged event fires whenever the user’s ID token gets changed.
  

• Session Updates:- Utilize this event for updating your app’s UI and backend logic in response to authentication state changes.

Troubleshooting Unexpected Session Expiration 

• Refresh Token Revocation:- If the user's refresh token is deleted, the session will end and the user will log out.
  

• Persistence Misconfiguration:- If session persistence is set to session or none, users may be logged out when they close or refresh the browser.
  

• Network Issues:- If the app cannot reach the Firebase to refresh the token, the session may expire.
  

• Custom Token use:- When using signInWithCustomToken make sure that the backend is not issuing tokens that expire prematurely.
  

• App Bugs:- Make sure your logout logic is not being triggered unintentionally and check for errors in your authentication stable management.

Device Browser and Storage Issue

Why do users get logged out after closing the browser or tab in Firebase?

If the users are being logged out after closing the tab, then your app is likely to be settled to sessionStorage for Firebase Auth persistence. This is a choice for apps that manage sensitive data or are used on shared devices. 

How Browser privacy settings can trigger unexpected logouts in firebase?

Advance browsers provide privacy settings that can:

• Block or Clear cookies and site data on exit.

• Restrict access to storage APIs.

• Automatically clear browsing data after every session.

If the users allow these settings, Firebase Auth may lose access to the stored authentication tokens. This can cause users to be logged out unexpectedly.

How Incognito Mode Affects Firebase Auth Sessions?

Incognito browsing modes isolate storage from the actual browser profile. In incognito mode:

• All Storage is temporary.

• Database cleared when the Incognito session ended.

This means that users will be always logged out whenever they close the incognito windows. Also some browsers restrict or block storage APIs in private mode. This can also avoid Firebase Auth from working as expected.

How Third-Party Cookies and Browser Extensions Interfere with Firebase Auth?

• Third-Party Cookies:- Firebase Auth may depend on third-party cookies to complete authentication flows. If a user blocks third-party cookies, authentication can fail or sessions may not persist.
  

• Browser Extension:- Privacy focused extensions can block or clear the cookies. This will interfere with Storage APIs. Also this will block network requests to Firebase endpoints. 

Custom Session Management

Implementing Custom Session Timeout Logic

Firebase does not support custom session timeout. But you can implement this logic by yourself.

• Track Last Activity:- Store a timestamp of user activity.

• Set a Timer:- Use a timer to check inactivity duration.

• Force Sign-Out:- If inactivity requires threshold, call firebase.auth(),signOut() to log the user out.

Example 

let lastActivity = Date.now();

document.onmousemove = document.onkeypress = () => lastActivity = Date.now();

setInterval(() => {

  if (Date.now() - lastActivity > SESSION_TIMEOUT_MS) {

    firebase.auth().signOut();

  }

}, 60000); // Check every minute

Create a Remember me Feature through Firebase Persistence Settings

Firebase auth supports three persistence types:

• local:- Persists across tabs and browser restart.

• session:- Persists only in the current tab/session.

• none:- Does not persist after the page is closed.

Example

// On login form submission

const persistence = rememberMeChecked

  ? firebase.auth.Auth.Persistence.LOCAL

  : firebase.auth.Auth.Persistence.SESSION;

firebase.auth().setPersistence(persistence)

  .then(() => firebase.auth().signInWithEmailAndPassword(email, password));

Extending Session Lifetimes for Enterprise or Regulated Apps

Some enterprise or regulated environments need extended sessions. While you can’t directly change Firebase token expiry, then

• Use background token refresh.

• Apply custom claims and session cookies through Firebase Admin SDK.

• Observe the user activity and prompt for re-authentication as required.

Use Background Token Refresh to Avoid User Disruption

Firebase automatically refreshes the ID tokens in the background as long as the app is open and the user is active. If you lose your network connectivity, token refresh may fail that results in logout.

• Listen to Auth State:- Use onAuthStateChanged to detect and manage logout events gracefully.
   

• Prompt for Re-Login:- If the user is logged out, show a login prompt rather than failing silently.
  
  

• Keep App Active:- For long sessions, promote periodic user activity or use background tasks to trigger token refresh.

Debugging and Best Practices

Common Mistakes When Managing Firebase Sign-out Events

Various problems can result in users to be logged out unexpectedly or avoid logout from working as expected.

• Not using Firebase Built-in Sign-out Method:- Some developers try to manage logout by manually deleting tokens instead of using official firebase.auth().signOut() method. This results in inconsistency in authentication state and issues such as session replay or incomplete logout.
  
  

• Not Logging out from External Providers:- While using federated identity providers, failing to sign out from the provider itself can result in users being automatically re-authenticated without a prompt.
  
  

• Improper Session Storage Management:- Depending only on local storage for tokens or user data without connecting with Firebase’s auth state can result in stale or orphaned sessions.

Below are some solutions to the problem

• Always use firebase.auth().signOut() sign out users.

• Trigger a signout from provider SDK if you want to fully clear the session.

• Remove user data from local/session storage only after signout is confirmed.

• Initialize Firebase once at app startup, not in every auth related function.

Best method for Cleaning up Auth Listeners to Prevent Memory Leaks

When using listeners such as onAuthStateChanged, always unsubscribe when the component or listeners are no longer required.

const unsubscribe = firebase.auth().onAuthStateChanged(user => {

  // Handle auth state

});

// Later, when cleaning up:

unsubscribe();

Diagnosing and Fixing “Logout not working” issue in Firebase

If the logout is not working as intended, consider to follow the below troubleshooting steps:

• Check for External Provider Sessions:- Make sure you are also logging out from the provider, not just Fiberbase.
  
  

• Clear Local Data After Sign-out:- Remove any cached tokens or user data from storage only after sign-out is complete.
  
  

• Prevent Several Firebase Instances:- Only start Firebase once at app Startup.
  
  

• Use correct sign-out method:- Everytime use the official signOut() method not custom logic or server endpoints.
  
  

• Manage Errors Gracefully:- Catch and log errors from signOut() to diagnose problems such as network failure or SDK misconfiguration.

Conclusion

User logout in Firebase/Auth can result from a range of factors, including token expiry, storage misconfiguration and browser privacy settings. By understanding these areas and following Firebase recommended practices, you can reduce unexpected logouts and offer a smooth authentication experience.