What is a push notification?

A message your app's server delivers to the user's device through Apple Push Notification service (APNs on iOS) or Firebase Cloud Messaging (FCM on Android). Shown on lock screen, notification center, and as a banner. Done well, drives 20-40% of DAU in habit-formation apps. Done poorly, drives users to disable notifications and eventually uninstall.

What is a good push notification opt-in rate?

iOS: cold prompts get 30-40% opt-in; well-designed value pre-prompts ("Allow notifications to get reminders about your favorite content") lift to 50-70%. Android 13+: 70-90% (lower friction than iOS prompt). Web push: 5-20% (users associate browser push with spam). Pre-prompt design matters — explain the value before showing the system prompt.

How many push notifications should I send?

Category-dependent. News / messaging / social: 5-15 per day acceptable. Habit-formation (fitness, learning, finance): 1-3 per day. Games: 1-3 per day around in-game events. Subscription / productivity: 0.5-2 per day. Utilities: 0.1-1 per day. Cross your category's threshold and opt-out rate rises, then uninstall rate. Relevance > volume.

Push Notifications — Mobile App Re-Engagement's Single Biggest Lever

Push notifications are messages your app's backend delivers to a user's device through Apple Push Notification service (APNs on iOS) or Firebase Cloud Messaging (FCM on Android). Done well, push is the single biggest re-engagement lever in mobile — driving 20-40% of DAU in habit-formation apps. Done poorly, push is a fast path to notification opt-out, app uninstall, and permanent loss of the user.

How a push notification flows from your server to the user — four steps, all gated on opt-in.

Opt-in rate reality

iOS: Apple requires explicit opt-in for push (UNNotification authorization). Cold prompts get 30-40% opt-in; well-designed value pre-prompts ("Allow notifications to get reminders about your favorite content") lift to 50-70%.
Android: through Android 12, push notifications were enabled by default — apps could send notifications immediately. Android 13+ (2022+) added an opt-in prompt similar to iOS; opt-in rates 70-90% (lower friction than iOS prompt).
Web push (PWAs / mobile web): much lower opt-in, 5-20% — users associate browser push with spam.

Frequency cap discipline

News / messaging / social: 5-15 pushes per user per day acceptable (high natural relevance — breaking news, friend messages).
Habit-formation apps (fitness, learning, finance): 1-3 pushes per day. Daily-streak nudge, content-update notification.
Casual / mid-core games: 1-3 pushes per day around in-game events.
Subscription / productivity: 0.5-2 pushes per day (rare-event-driven).
Utilities: 0.1-1 push per day (high-relevance only — weather alerts, transit warnings, scheduled reminders).

Cross this threshold and notification opt-out rate rises, then uninstall rate. The user's trust is the resource — spend it on actually-relevant notifications.

Major push platforms

Braze — enterprise-leading customer engagement platform with strong push + email + in-app messaging orchestration.
Iterable — comparable to Braze, popular at growth-stage companies.
Customer.io — strong at SMB / mid-market, developer-friendly.
OneSignal — broad-market push platform, free tier popular with smaller apps.
Firebase Cloud Messaging (FCM) — Google's underlying message-delivery system, often used directly by apps that want full control of orchestration. Free at scale.
In-house orchestration — possible but rarely worth it; the cross-platform delivery + segmentation + A/B testing is complex.

Push vs email vs SMS — when to use each channel

Channel	Delivery	Open rate	Cost	Reach requirement
Push notification	Instant (seconds)	4-10%	Free (APNs / FCM are platform-owned)	App must be installed + user opted in
Email	~minutes	20-25%	$0.10-1.00 per 1,000 emails	Have a valid email address
SMS	Instant	90%+	$0.01-0.05 per message	Have a valid phone number + opt-in
WhatsApp Business	Instant	90%+	$0.005-0.10 per message (geo-tiered)	WhatsApp Business API access + user opt-in
In-app messaging	Only when user opens the app	~80% (user is in session)	Free (no carrier or network fee)	User actively in the app right now

Most mature consumer apps combine all five. Push handles the time-sensitive nudges; email handles the deeper content + win-back; SMS is reserved for high-stakes confirmations; in-app messaging handles upsell / education while users are already engaged.