The Firebase Realtime Database is a NoSQL cloud-hosted database. The data is stored as JSON and it allows syncing of data across all the clients in real time. No matter which platform you are building on, using Firebase, all your clients share one realtime database instance. Firebase uses a data synchronization mechanism with which, every time the data changes, any connected device can receive new updates within no time.
This is how the Firebase uses realtime sync, rather than just a typical HTTP request:
One of the biggest pains for developers is to ensure data remains available, even when the app is offline. Firebase-built apps allow apps to remain responsive when your device goes offline. This is possible as Firebase Realtime Database SDK maintains your data to disk, ensuring that it can be available while offline...
