Optimized for Offline Use
When users go offline, the Realtime Database SDKs utilize local cache on the device to effective serve and store changes. When the devices receive connection, the local data is automatically synchronized.
Accessible from Devices
The Firebase Realtime Database can be accessed from a mobile device or even web browser. Hence, there is no need of an application server. Security and data validation are available through the Firebase Realtime Database security and expression-based rules.
Powerful User-Based Security
The Realtime Database integrates with Firebase Authentication in order to offer simple as well as intuitive authentication for developers. By using security model, you can allow access based on user identity or with pattern matching on your data.
It enables you to build rich and collaborative apps by paving the way for secure access to the database directly from client-side code. There is nothing wrong in saying that data is persisted locally and during offline, realtime events continue to work, offering a great user experience. On the other hand, when the device regains connection, the Realtime Database effectively synchronizes the local data changes with the remote updates during offline.
It provides flexible and expression-based rules language which is known as Firebase Realtime Database Security rules. The main motive is to define how the data should be structured. It is a NoSQL database and has different optimizations as well as functionality in comparison to a relational database. Realtime Database API is designed to allow operations that can be executed in a quick manner. This way you can build a great realtime experience.