Introduction to the Firebase Realtime Database

Get a brief introduction to Firebase Realtime Database.

The Firebase Realtime Database is a scalable, real-time NoSQL cloud database provided by Firebase for storing application data. Data is stored as a JSON tree and synchronized in real time across multiple client applications.

How it works

The Firebase Realtime Database lets us store and sync data between users in real time. This makes it easy for users to access their data on any device—web or mobile— and helps users collaborate. Whenever data is updated in the Realtime Database, it stores the data in the cloud and updates all connected devices instantly. The Firebase Realtime Database persists data to the local cache, therefore making it optimized for offline usage. Whenever a user goes offline, it uses the device’s local cache to store data and synchronizes both the cloud data and the local data when the user is online.

With the security rules, we can control users’ access to each database on our application. This is useful in securing the database and authorizing user operations. It also makes sure that users only have access to their data.


Before using the Firebase Realtime Database, we must import and initialize the Firebase Database service. To begin, we import the getDatabase function from the firebase/database subpackage. Then, we initialize the Firebase database by calling the getDatabase function. We can also pass the Firebase App instance to it:

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