Firebase Interview Questions and Answers

Firebase is a lightweight Google-backed app development software for Web Apps and Mobile Applications (iOS and Android). Firebase has different services include real time database, different APIs, multiple authentication types and hosting platform. It was founded by James Tamplin and Andrew Lee in Sep,2011, then acquired by Google in 2014.

Firebase offers number of services. Firebase services divides into two groups.

Develop & test your app (Build Your App)

• ML Kit
• Authentication
• Realtime Database
• Test Lab
• Cloud Functions
• Cloud Firestore
• Cloud Storage
• Performance Monitoring
• Crash Reporting
• Firebase Hosting
• Crashlytics
• App distribution

Grow & Engage your audience (Grow Your App)

• Firebase Analytics
• Cloud Messaging
• Predictions
• Remote Config
• A/B Testing
• Dynamic links
• In App messaging

• Real Time Database
• Automatic Scaling
• Strong Data Security
• Real time Synchronization
• Data Accessibility
• Servers are optional
• Client-side code option
• JSON storage
• Advanced BaaS

These are official Firebase SDKs for use in Mobile and Web Applications

• Android SDK
• iOS SDL
• Unity SDK
• C++ SDK
• JavaScript SDK

• AngularFire
• FlutterFire
• EmberFire
• VueFire
• React NativeFire
• RxFire
• ReactFire

FCM stands for Firebase Cloud Messaging. FCM  provides a reliable and battery-efficient connection between server and devices that allows to deliver and receive messages and notifications on iOS, Android, and Web at without charges.

Robo Script is a JSON file that has a set of actions that robo can perform in the given order. One of the best services in Firebase Test Labs called Robo Test that allows us to test our app with having to write any test scripts.

Cloud Firestore is a flexible as well as scalable NoSQL cloud database. Firestore is used to store and sync data for client and server-side development. Cloud Firestore is mainly used for mobile, web, and server development from Google Cloud Platform and Firebase.

Firebase Hosting allows fast and secure hosting for our web application, static and dynamic content, and microservices. It is production-grade web content hosting for the developers. We can easily and quickly deploy web apps and serve both static and dynamic content to a global content delivery network with only a single command.

Firebase Cloud Function is a Google analog that is taken into used to develop applications which are serverless. The Cloud Functions for firebase allows running the code of backend itself as a reaction to the HTTP requests and Firebase’s triggered events. There is no more need for managing and increasing one’s own server since the data is being kept in Google’s cloud which runs in a safe and managed atmosphere.

TypeScript and JavaScript can be used for writing the functions. The Firebase features and Google Cloud feature’s events generated by them, the functions can react to these events including Real-time database triggers and Cloud Storage triggers.

Rule Types:

• . read
• . write
• . validate
• .indexon

• 5228-Main Post
• 5229-Optional
• 5230 -Optional

Firebase project is a container for apps. It supports many features such as Database, Config and Notifications between your cross-platform apps.

This method is triggered when a child is removed from the location to which this listener was added.

Using startAt(), endAt(), and equalTo() allows you to choose arbitrary starting and ending points for your queries.

Firebase delivers data to us with five different events accessed with ref.on(“event,callback”);

• Value
• Child_added
• Child_changed
• Child_moved
• Child_removed

These four methods for writing data to your Firebase Realtime Database.

• set
• update
• push
• transaction

By using, signInWithEmailAndPassword(email, password) method.

The Transactional data is used to return some data from the database.

Order Functions are great for Sorting Data,

• orderByChild()
• orderByKey()
• orderByValue()