The Firebase Realtime Database is a cloud-hosted database. Data is stored as
JSON and synchronized in realtime to every connected client. When you build
cross-platform apps with our Android, Apple platforms, and JavaScript SDKs, all of your
clients share one Realtime Database instance and automatically receive
updates with the newest data.
Prerequisites
If you haven't already,
install the Firebase JS SDK and initialize Firebase
.
Create a Database
Navigate to the
Realtime Database
section of the
Firebase console
.
You'll be prompted to select an existing Firebase project.
Follow the database creation workflow.
Select a starting mode for your Firebase Security Rules:
- Test mode
Good for getting started with the mobile and web client libraries,
but allows anyone to read and overwrite your data. After testing,
make
sure to review the
Understand Firebase Realtime Database Rules
section.
To get started with the web, Apple, or Android SDK, select testmode.
- Locked mode
Denies all reads and writes from mobile and web clients.
Your authenticated application servers can still access your database.
Choose a location for the database.
Depending on the
location of the database
, the
URL for the new database will be in one of the following forms:
Click
Done
.
When you enable Realtime Database, it also enables the API in the
Cloud API Manager
.
The Realtime Database provides a declarative rules language that allows you to
define how your data should be structured, how it should be indexed, and when
your data can be read from and written to.
Add the Realtime Database JS SDK and initialize Realtime Database
You must specify your Realtime Database URL when initializing the JavaScript SDK.
You can find your Realtime Database URL in the
Realtime Database
section of the
Firebase console
. Depending on the
location of the database
,
the database URL will be in one of the following forms:
https://
DATABASE_NAME
.firebaseio.com
(for databases in
us-central1
)
https://
DATABASE_NAME
.
REGION
.firebasedatabase.app
(for databases in all other locations)
Initialize the SDK using the following code snippet:
Web modular API
import { initializeApp } from "firebase/app";
import { getDatabase } from "firebase/database";
// TODO: Replace the following with your app's Firebase project configuration
// See: https://firebase.google.com/docs/web/learn-more#config-object
const firebaseConfig = {
// ...
// The value of `databaseURL` depends on the
location of the database
databaseURL:
"https://
DATABASE_NAME
.firebaseio.com"
,
};
// Initialize Firebase
const app = initializeApp(firebaseConfig);
// Initialize Realtime Database and get a reference to the service
const database = getDatabase(app);
Web namespaced API
import firebase from "firebase/app";
import "firebase/compat/database";
// TODO: Replace the following with your app's Firebase project configuration
// See: https://firebase.google.com/docs/web/learn-more#config-object
const firebaseConfig = {
// ...
// The value of `databaseURL` depends on the
location of the database
databaseURL:
"https://
DATABASE_NAME
.firebaseio.com"
,
};
// Initialize Firebase
firebase.initializeApp(firebaseConfig);
// Initialize Realtime Database and get a reference to the service
const database = firebase.database();
You're ready to start using the Firebase Realtime Database!
Next Steps