Implementing Rich Push Notifications in Mobile Apps

Standard notifications—just a title and text. Clients complain they are ignored. We implement Rich Push: images, action buttons, sometimes video. On iOS, this requires a Notification Service Extension; on Android, BigPictureStyle. Our experience shows such notifications increase CTR by 40% and engagement by up to 70%. Below we cover both approaches with real examples.

How to Configure Rich Push on iOS?

Without NSE, images in push on iOS won't work. NSE is a separate target in Xcode that intercepts the notification before display. It downloads media and attaches it as a UNNotificationAttachment. We guarantee compatibility with the latest iOS versions.

// NotificationService.swift
class NotificationService: UNNotificationServiceExtension {
    override func didReceive(_ request: UNNotificationRequest,
                             withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void) {
        let content = request.content.mutableCopy() as! UNMutableNotificationContent

        guard let urlString = content.userInfo["image_url"] as? String,
              let url = URL(string: urlString) else {
            contentHandler(content)
            return
        }

        downloadImage(from: url) { localURL in
            if let localURL,
               let attachment = try? UNNotificationAttachment(identifier: "image",
                                                               url: localURL) {
                content.attachments = [attachment]
            }
            contentHandler(content)
        }
    }

    private func downloadImage(from url: URL, completion: @escaping (URL?) -> Void) {
        URLSession.shared.downloadTask(with: url) { tempURL, _, _ in
            completion(tempURL)
        }.resume()
    }
}

NSE has a run limit of about 30 seconds. If media does not download, iOS shows the notification without an image. We optimize media: size up to 1 MB, JPEG or PNG format. According to Apple documentation, exceeding the limit hides the image.

Action buttons on iOS. Register categories at app launch:

let likeAction = UNNotificationAction(identifier: "LIKE", title: "Like", options: [])
let replyAction = UNNotificationAction(identifier: "REPLY", title: "Reply", options: [.foreground])
let category = UNNotificationCategory(identifier: "POST_CATEGORY",
                                       actions: [likeAction, replyAction],
                                       intentIdentifiers: [])
UNUserNotificationCenter.current().setNotificationCategories([category])

In the notification payload, include category: "POST_CATEGORY" — iOS will display the buttons. Handle taps:

func userNotificationCenter(_ center: UNUserNotificationCenter,
                             didReceive response: UNNotificationResponse,
                             withCompletionHandler completionHandler: @escaping () -> Void) {
    switch response.actionIdentifier {
    case "LIKE":
        likePost(id: response.notification.request.content.userInfo["post_id"] as? String)
    case "REPLY":
        openReplyScreen(for: response.notification.request.content.userInfo)
    default:
        break
    }
    completionHandler()
}

Why Data Message is Preferable to Notification Message on Android?

On Android, custom UI natively:

val bitmap = BitmapFactory.decodeStream(
    URL(imageUrl).openConnection().getInputStream()
)

val notification = NotificationCompat.Builder(context, CHANNEL_ID)
    .setSmallIcon(R.drawable.ic_notification)
    .setContentTitle(title)
    .setContentText(body)
    .setStyle(
        NotificationCompat.BigPictureStyle()
            .bigPicture(bitmap)
            .setSummaryText(body)
    )
    .addAction(
        R.drawable.ic_like,
        "Like",
        getLikePendingIntent(postId)
    )
    .addAction(
        R.drawable.ic_reply,
        "Reply",
        getReplyPendingIntent(postId)
    )
    .build()

Loading bitmap must not be on main thread. Use Glide or WorkManager. FCM Data Message is the correct approach, because Notification Message is handled by the system without calling your code. Data Message always goes to onMessageReceived. In real projects, Data Message is more reliable: when the app is killed, Notification Message does not guarantee image display, but Data Message does.

Media Formats

Step-by-Step Integration Guide

1. Assess push architecture — determine whether FCM or a third-party service is used.
2. Design categories and payload — define notification types, action buttons, media fields.
3. Implement NSE on iOS — create target, add download and attachment code.
4. Implement BigPictureStyle on Android — configure Data Message, use NotificationCompat.
5. Test on real devices — verify all scenarios (active/background/killed app).
6. Deploy and monitor — publish to stores, track clicks.

Timeline and What's Included

Included: NSE setup, category registration and tap handling on iOS; FCM Data Message and BigPictureStyle integration on Android; testing on both platforms; documentation. Not included: custom Notification Content Extension and analytics — discussed separately. Pricing is determined after analyzing your project.

Common Mistakes

• OneSignal and NSE. If using OneSignal, add the OneSignalNotificationServiceExtension target to App Groups. Otherwise images won't appear without error logs.
• Dual payload on Android. Using both notification and data fields in FCM when the app is killed causes onMessageReceived not to be called. Use only data payload.
• Media size. On iOS, media over 1 MB may not download within 30 seconds. On Android, large images cause OutOfMemoryError. Optimize to 500 KB.

Why Trust Us

We have many years of experience in mobile development and have delivered over 30 projects with push notifications. We guarantee compatibility with the latest iOS and Android versions, compliance with App Store Review Guidelines. We handle up to 1000 notifications per minute without performance loss. Request rich push integration for your app — we'll prepare a proposal within one day. Get a free consultation for your project to estimate savings.

Sources: UNNotificationServiceExtension — Apple Developer Documentation, BigPictureStyle — Android Developers

Push Notifications in Mobile App: APNs, FCM, Segmentation, Rich Push

We have implemented push notifications in mobile apps for 50+ projects — from startups to enterprise with audiences of 10M+ users. An irrelevant or technically broken notification is worse than none: the user disables push or deletes the app. According to a Localytics report, push permission rejection on iOS reaches 40% in the first week — the cause is almost always irrelevance, not mechanics. Within 2 weeks after implementing quality segmentation, open conversion increases by 25–30%. Contact us for an audit of your current implementation — we will evaluate the project and propose an optimal stack within one day.

How the Infrastructure Works: APNs and FCM

APNs is the only delivery channel on iOS. Everything else (OneSignal, Braze, Airship) is a wrapper on top of it. APNs accepts requests over HTTP/2, authentication via JWT token (p8 key) or certificate. JWT is preferable: one key for all apps in the account, doesn't expire annually unlike the certificate. For more details, see the official documentation.

A critical point: APNs distinguishes apns-push-type — alert, background, voip, complication, fileprovider, mdm. An incorrect type on iOS 13+ causes background notifications not to wake the app. We've seen projects where content-available: 1 was sent without apns-push-type: background — the app didn't receive silent push on some devices, and the team spent a month looking for an 'app bug'.

FCM on Android works through Google Play Services. For devices without GMS (Huawei, part of the Chinese market), Huawei Push Kit or a direct WebSocket is needed — a separate task. FCM supports data messages (handled in onMessageReceived) and notification messages (the system displays automatically if the app is in the background). Mixing them requires caution: if the notification block has a click_action but the deep link is not registered in the app, tapping the notification simply opens the main screen without navigation.

Why Segmentation Is the Foundation of Effective Push Notifications?

Sending to everyone indiscriminately quickly exhausts user loyalty. Personalized messages are clicked 3 times more often than bulk ones, and proper segmentation reduces churn by 25% (on one project it brought significant additional revenue per quarter). The cost of setting up segmentation in OneSignal or a custom backend depends on the complexity of filters.

Proper segmentation is built on several levels.

Topics are for broad categories: 'new promotions', 'order status updates'. User subscribes via FirebaseMessaging.getInstance().subscribeToTopic("orders"). Simple, but no flexible filtering.

Attribute-based segments — via OneSignal, Braze, or custom backend. We store in the user profile: language, device type, last activity, LTV segment. Notification goes only to those with last_active < 7_days and plan = premium. OneSignal allows building such filters in the interface without code.

Personalized — by specific device_token. It's important to store tokens correctly: the token updates on app reinstall, restoration from backup on a new phone, or resetting settings. On iOS, use UNUserNotificationCenter + didRegisterForRemoteNotificationsWithDeviceToken, save to backend on every launch, not just the first. Otherwise, after 3 months 30% of tokens in the database are outdated.

What Is Rich Push and How Does It Boost Conversion?

A standard notification with title and text is clicked less often than a rich push with image and action buttons — by 3 times. But implementing rich push is a separate task on each platform.

On iOS, rich content requires UNNotificationServiceExtension (to modify payload) and UNNotificationContentExtension (custom UI). The extension runs in a separate process with limited time and memory. If the extension crashes or exceeds the timeout, the system shows the original payload without media. A typical mistake is trying to load an image over HTTP (not HTTPS): ATS blocks the request, the extension silently fails, and the user sees a notification without an image.

On Android with API 26+, notifications are tied to NotificationChannel. If the channel is created with IMPORTANCE_LOW, sound and vibration are unavailable. Different notification types (transactional, marketing) should be in different channels so the user can disable marketing without losing order notifications. BigPictureStyle, MessagingStyle, InboxStyle are templates for expanded notifications. MessagingStyle with Person and avatars is the best choice for chats.

How to Track Delivery and Conversion of Push Notifications?

Sending a notification is half the work. It's important to know: was it delivered, opened, and did it lead to a target action.

FCM returns a MessageId on send, but does not guarantee a delivery callback — by design. For open tracking, custom logic is needed: on notification tap in onMessageReceived or via getInitialNotification() / onNotificationOpenedApp (OneSignal SDK), send an event to analytics with notification_id.

OneSignal provides built-in delivery and CTR analytics. For more detailed analysis — integrate with Amplitude or Mixpanel via webhook on open events. The budget for such a dashboard varies depending on event volume.

How We Implement Push Notifications: Typical Process

1. Audit current implementation — check token storage, update handling, notification types.
2. Design architecture — choose transport (FCM + APNs), segmentation layer (OneSignal/Braze/custom), personalization method.
3. Implementation — write registration code, inbound handling, rich push, deep linking.
4. Testing — send test campaigns, verify delivery on different devices, simulators, regions.
5. Monitoring and analytics — set up dashboard, open and conversion events.
6. Documentation and training — hand over operational materials to the team.

Typical stack: FCM + APNs at transport level, OneSignal or Firebase Notifications Composer for segmentation, custom backend for personalized event-based notifications. For large apps with >1M users, OneSignal has pricing limits — then we use Braze or a custom implementation on AWS SNS.

Timelines depend on complexity: basic FCM+APNs integration with transactional notifications — 1–2 weeks. A full system with segmentation, rich push, analytics, and A/B testing — 4–8 weeks. Order an audit of your current push infrastructure or get a consultation on implementing push notifications in your mobile app — we will contact you within a day and provide an accurate estimate.