How to Schedule Push Notifications in FlutterFlow

Cloud Scheduler is Google Cloud's managed cron service. It sends an HTTP request to your Cloud Function on a schedule. In the Google Cloud Console (console.cloud.google.com), navigate to Cloud Scheduler and click Create Job. Set the frequency using cron syntax — for example, 0 9 * * * sends the notification at 9am every day. Set the target to HTTP, enter your Cloud Function's URL, set the method to POST, and add a body with any notification parameters. In your Cloud Function, call the Firebase Admin SDK's messaging().send() method to dispatch the notification to all subscribed users or a specific topic. Use FCM topics for broadcasting to all users: subscribe users to a topic on app launch using messaging().subscribeToTopic().

1// Cloud Function: sendDailyDigest
2// Triggered by Cloud Scheduler at 0 9 * * *
3const functions = require('firebase-functions');
4const admin = require('firebase-admin');
5
6exports.sendDailyDigest = functions.https.onRequest(async (req, res) => {
7  const message = {
8    notification: {
9      title: 'Your Daily Digest',
10      body: 'Here is what happened while you were away.',
11    },
12    topic: 'daily_digest', // all users subscribed to this topic
13  };
14
15  await admin.messaging().send(message);
16  res.status(200).send('Notification sent');
17});

For notifications at a specific user-defined time (booking reminder, event alert), write a document to a scheduled_notifications Firestore collection when the user schedules the notification. The document should contain: userId (String), fcmToken (String — the user's current FCM token), title (String), body (String), scheduledFor (Timestamp), sent (Boolean, default false). Create a Cloud Function using functions.pubsub.schedule('every 1 minutes') that queries scheduled_notifications where scheduledFor is less than or equal to now AND sent is false. For each matching document, send the notification via admin.messaging().send() and update sent to true. This polling approach scales to thousands of per-user notifications without hitting Cloud Scheduler limits.

1// Cloud Function: checkScheduledNotifications
2// Runs every minute via Pub/Sub schedule
3const functions = require('firebase-functions');
4const admin = require('firebase-admin');
5
6exports.checkScheduledNotifications = functions.pubsub
7  .schedule('every 1 minutes')
8  .onRun(async (context) => {
9    const now = admin.firestore.Timestamp.now();
10    const db = admin.firestore();
11
12    const due = await db
13      .collection('scheduled_notifications')
14      .where('scheduledFor', '<=', now)
15      .where('sent', '==', false)
16      .limit(100)
17      .get();
18
19    const batch = db.batch();
20    const sends = [];
21
22    due.docs.forEach((doc) => {
23      const data = doc.data();
24      sends.push(
25        admin.messaging().send({
26          token: data.fcmToken,
27          notification: { title: data.title, body: data.body },
28        })
29      );
30      batch.update(doc.ref, { sent: true });
31    });
32
33    await Promise.all(sends);
34    await batch.commit();
35    return null;
36  });

In FlutterFlow, create a reminder settings page or bottom sheet. Add a DateTimePicker widget (found under Form widgets) that lets the user pick a future date and time. Add a DropdownButton widget for repeat interval with options: Once, Daily, Weekly, Monthly. Add a Text input for the reminder label. Connect a Save button with an Action Flow that: (1) validates the selected time is in the future, (2) fetches the user's current FCM token using a Custom Action, (3) creates a Firestore document in scheduled_notifications with all the fields including scheduledFor set to the DateTimePicker value. For repeat notifications, also store repeatInterval and the Cloud Function handles rescheduling by writing a new document with the next occurrence time after sending.

FCM tokens change when a user reinstalls the app, clears app data, or the token is rotated by Firebase. If you store a stale token in a scheduled_notifications document, the notification will silently fail to deliver. In FlutterFlow, add an On App Launch action that calls a Custom Action to refresh the FCM token and update the token field in the user's Firestore document. When the Cloud Function sends a notification and receives a messaging/invalid-registration-token error, delete the corresponding scheduled_notifications document and log the failure so the user can reschedule. This keeps your scheduled_notifications collection clean and delivery rates high.