All 15 Email & Notifications questions
More in Email & Notifications
What is Nodemailer, and how does it let a Node.js application send emails via SMTP? What is the difference between the 'to', 'cc', and 'bcc' fields when sending an email programmatically, and why does 'bcc' matter for privacy? Why should sending an email typically happen in a background job rather than synchronously within an HTTP request handler? What is email template rendering, and how might you use a templating engine to generate dynamic HTML emails in Node.js? What is the difference between transactional email and marketing email, and why do most Node.js applications use separate providers or sending domains for each? What is an unsubscribe mechanism, and what specific requirements does it need to meet for compliance with regulations like CAN-SPAM? What is the difference between sending SMS via a provider's REST API (like Twilio) versus using SMTP-based email in terms of a Node.js integration? How would you test that a Node.js application correctly sends emails without actually sending real emails during automated tests? What are SPF, DKIM, and DMARC, and why do they matter for a Node.js application's transactional emails actually reaching users' inboxes? How would you design a multi-channel notification system in Node.js that can send the same logical notification via email, SMS, or push depending on user preference?
Advertisement
Back to results for “Background Jobs & Queues”
Node.js › Email & Notifications

How would you send a push notification from a Node.js backend to a mobile app using Firebase Cloud Messaging (FCM)?

Intermediate

Answer

The backend uses the Firebase Admin SDK, authenticated with a service account, to send a message targeting a specific device (via a registration token the client app previously obtained and sent to the backend) or a topic (letting multiple subscribed devices receive the same message) -- FCM then handles actual delivery to the device across both iOS and Android.
const admin = require('firebase-admin');
admin.initializeApp({ credential: admin.credential.cert(serviceAccount) });

await admin.messaging().send({
  token: userDeviceToken,
  notification: { title: 'Order Shipped', body: 'Your order is on its way!' },
});
Real-world example An e-commerce app sends a push notification via FCM to a customer's phone the moment their order ships, using the device token the mobile app registered and sent to the backend during login.

Common follow-ups: How do you handle an invalid or expired device token returned by FCM when sending a notification?;What's the difference between targeting a specific device token versus a topic subscription for broadcast notifications?

HTTP & HTTPS Modules;Background Jobs & Queues
All 15 Email & Notifications questions