How to Send Push Notifications to Multiple FCM Tokens in Node.js

f you're working with Firebase Cloud Messaging (FCM) and want to send push notifications to multiple devices at once, you'll be using the registration_ids property.

Here’s a practical function using Node.js, that sends push notifications to multiple FCM tokens:

export const sendPush = async (params: any) => {
    try {
        let message: any = {};

        // Set up the notification payload
        message.notification = {
            title: params.title,                    // Notification title
            body: params.body,                      // Notification body
            data: params.data,                      // Additional custom data
            content_available: true,                // Enable background notifications
            priority: "high",                       // High priority for immediate delivery
            sound: "default",                       // Default notification sound
        };

        // Additional data payload (optional)
        message.data = params.data;

        // Deduplicate tokens to avoid sending multiple times to the same device
        message.registration_ids = [...new Set(params.token)];

        // Send the notification via FCM
        return await fcm.send(message);
    } catch (err) {
        // Log and return any errors
        logger.logger.error(err);
        return err;
    }
};

🔍 Explanation

• params.title & params.body
  These are the notification title and body text that will appear on the device.

• params.data
  Custom data you want to send along with the notification. This can include deep-linking information, IDs, or any payload your app might need.

• content_available: true
  This flag enables background notifications (especially useful for iOS).

• priority: "high"
  Ensures that the notification is delivered immediately (useful for time-sensitive notifications).

• sound: "default"
  Plays the default notification sound on the device.

• message.registration_ids

  • This is an array of FCM device tokens (also called registration tokens).

  • We wrap it with new Set() and spread into an array to ensure no duplicate tokens are included in the request.

• fcm.send(message)
  Finally, we send the message using the FCM service.

• Error Handling
  Any errors during the process are caught, logged, and returned.

✅ Usage Example

Here’s how you might call this function:

await sendPush({
    title: 'New Offer!',
    body: 'Check out our latest discounts.',
    data: { offerId: '1234' },
    token: [
        'fcm_token_1',
        'fcm_token_2',
        'fcm_token_3',
        // ...more tokens
    ],
});

🚀 Notes

• The registration_ids option allows you to send up to 500 device tokens in a single API request.
• If you have more than 500 tokens, you’ll need to split them into multiple requests.
• Make sure you handle responses to remove invalid or expired tokens from your database!