Push notification

A push notification is the only piece of an app that runs when the app does not. A server sends it, the operating system draws it, and the app has almost no say in how it looks: a banner over whatever the person was doing, a card on the lock screen, a row in the notification list, a count on the icon. What the app controls is the text, the grouping, and the destination the tap leads to. Everything else belongs to the platform, which is why the same message reads differently on two phones and why designing one means writing rather than styling.

The word that gets confused with it is toast. A toast lives inside a running app, appears in a corner of a screen the person is already looking at, needs no permission, and disappears on its own. A push notification needs an explicit grant before a single one can be delivered, survives until it is dismissed, and reaches someone who is not using the app at all. They answer opposite questions. Confirming that a file saved is a toast; telling someone their delivery is two stops away is a push. The count that accumulates on the app icon is a badge, which is the quiet register of the same system and the right place for anything that does not justify a sound.

Permission is the hinge, and it is spent once. On both platforms a person who declines is very hard to ask again, so asking on first launch, before the app has done anything worth being told about, is how a product loses the channel permanently. Prime it instead: explain in your own interface what will be sent and how often, ask only when someone has just done the thing that produces a notification (placed an order, followed a thread), and treat a refusal as an answer rather than a state to nag out of. Give people per type controls afterwards, because the alternative to a switch they can find is the system level off switch, which takes everything with it.

Then earn each one. The useful test is whether the message would be worth waking a phone in a pocket for, and the honest answer for most marketing pushes is no. Write the important half in the first few words, since a banner truncates and a lock screen may be set to hide the content entirely. Group related messages into a thread instead of stacking eight separate rows. Deep link to the exact screen the notification is about, never to the home screen. And remember that a notification tapped a day later is still expected to work, which means the destination has to exist even when the event it announced has moved on.