FCM setup in Firebase - Step-by-Step Execution

Process Flow - FCM setup

Create Firebase Project

↓

Enable Cloud Messaging

↓

Download config file

↓

Add config to app

↓

Initialize Firebase in app

↓

Request user permission

↓

Get FCM token

↓

Send/Receive messages

This flow shows the steps to set up Firebase Cloud Messaging from project creation to sending and receiving messages.

Execution Sample

Firebase

firebase.initializeApp(firebaseConfig);
const messaging = firebase.messaging();
messaging.requestPermission()
  .then(() => messaging.getToken())
  .then(token => console.log(token));

This code initializes Firebase, requests permission for notifications, and retrieves the FCM token.

Process Table

Step	Action	Result	Next Step
1	Initialize Firebase with config	Firebase app ready	Request permission
2	Request notification permission	Permission granted	Get FCM token
3	Get FCM token	Token received: abc123	Use token to send messages
4	Use token to send message	Message sent successfully	Listen for messages
5	Receive message	Message displayed to user	End
6	Permission denied or error	No token received	Stop setup

💡 Setup ends after receiving token and sending/receiving messages or if permission denied.

Status Tracker

Variable	Start	After Step 2	After Step 3	Final
firebaseApp	null	initialized	initialized	initialized
permission	not requested	granted	granted	granted
fcmToken	null	null	abc123	abc123
messageStatus	none	none	sent	received

Key Moments - 3 Insights

Why do we need to request permission before getting the FCM token?

Because the token is only issued if the user allows notifications, as shown in execution_table step 2 and 3.

What happens if the user denies permission?

No token is received and setup stops, as shown in execution_table step 6.

Why do we initialize Firebase before requesting permission?

Firebase must be ready to handle messaging requests, as shown in execution_table step 1.

Visual Quiz - 3 Questions

Look at the execution table, what is the result after requesting permission?

A Message sent

B Permission granted

C Token received

D Permission denied

💡 Hint

Check step 2 in the execution_table for the permission request result.

At which step does the FCM token get received?

A Step 1

B Step 5

C Step 3

D Step 6

💡 Hint

Look at the 'Result' column in execution_table step 3.

If the user denies permission, what happens to the token variable?

A It stays null

B It becomes 'abc123'

C It becomes 'permission denied'

D It gets deleted

💡 Hint

Refer to variable_tracker for 'fcmToken' after step 2 and step 6.

Concept Snapshot

FCM setup steps:
1. Create Firebase project and enable Cloud Messaging.
2. Download config and add to app.
3. Initialize Firebase in app code.
4. Request user permission for notifications.
5. Get FCM token if permission granted.
6. Use token to send and receive messages.

Full Transcript

To set up Firebase Cloud Messaging (FCM), first create a Firebase project and enable Cloud Messaging. Download the configuration file and add it to your app. Initialize Firebase in your app code. Then request the user's permission to send notifications. If permission is granted, get the FCM token. Use this token to send messages to the device. The device can then receive and display messages. If permission is denied, no token is received and setup stops.