Retention emails vs push notifications: which to use, Whisperr

Push vs email at a glance

	Push notification	Email
Who it reaches	Users with the app installed and notifications allowed	Users with an address you may write to
Best for	Short, timely nudges: a streak, a next step, a reminder tonight	Longer messages: trial reminders, payment issues, win-back
Length	A line or two	As long as it needs, though short still wins
Reaches users who deleted the app	No	Yes
Main risk	The user turns notifications off for good	Spam folder, unsubscribes
Timing	Lands at once, so quiet hours matter	Read later, so timing is looser

When push works best

Push is the right channel when the message is short, the moment matters and the user still has your app. “2 lessons left in Spanish Basics. Ten minutes tonight and you’re done.” It lands on the lock screen and one tap opens the right screen.

Because push interrupts, it’s also the easiest channel to burn. A user who gets one push too many turns notifications off, and after that every future message has to go by email. Respect quiet hours in the user’s own time zone and cap how often anyone hears from you.

When email works best

Email reaches users push can’t: those who never allowed notifications, turned them off or deleted the app. It suits messages that need a few sentences, such as a trial ending in three days, a payment that failed, or what’s new since a user left.

Email needs an address you’re allowed to write to, an unsubscribe link and a sending domain set up for deliverability. If users sign in with Apple and hide their address, you need to register your sending domain with Apple to reach the relay address.

Choose per user, not per campaign

A campaign that goes out “by push” misses everyone who turned push off. A campaign that goes out “by email” wastes a slow channel on users who would have tapped a push. The better rule is to pick, for each user and each message, the channel they can receive and are most likely to welcome, and to send it on only one.

Where Whisperr fits

Whisperr picks push or email for each user, based on what they have opted into and can receive, and sends through your own providers: OneSignal, Firebase Cloud Messaging, Apple Push or Expo for push, and Postmark, Resend or SendGrid for email. It holds messages during quiet hours in the user’s local time, applies daily and weekly caps and cooldowns, and sends nothing to users who don’t need it. Each message is written for that user, in your app’s voice and in their language.

FAQ

Is push or email better for retention?

It depends on the user and the moment. Push works for quick, timely nudges when the user has the app and notifications on. Email works for longer messages and for users who can't get push. The better question is which channel this user can receive and would welcome right now.

Why don't all my users get push notifications?

On iOS, users must allow notifications, and on Android 13 and later apps must ask for permission too. Users can also turn notifications off at any time or delete the app. A share of your users will only ever be reachable by email, if at all.

How many retention push notifications is too many?

There's no universal number, but every message a user didn't need makes them more likely to turn notifications off. Set caps per day and per week, a cooldown between messages and quiet hours in the user's time zone, and send nothing to users who are doing fine.

Should I send the same message by push and email?

Usually not. Sending both doubles the interruption for one idea. Pick one channel per message per user, and use the other only if the first can't reach them.

Which channels does Whisperr use?

Push and email. Whisperr chooses per user based on what they have opted into and can receive, and sends through your own providers. For push that's OneSignal, Firebase Cloud Messaging, Apple Push or Expo, and for email Postmark, Resend or SendGrid.

Retention emails vs push notifications, which works better?