Wirebook › Glossary › Push notification
What is a push notification?
In one sentence: A message a website or app sends to your device the moment something happens, so the device doesn't have to keep asking.
A little more
A push notification is news sent to your device as soon as it happens, instead of your device asking for it. The app registers once and gets an address; when there's something new, the website sends a message to that address through a push service run by the phone or browser maker.
The push service acts like a post office: if your phone is asleep, out of signal or switched off, it holds the message and delivers it when the phone comes back. That's why a pile of notifications can arrive at once when you leave a tunnel. Apps can only push to you after you allow notifications, and you can turn them off any time.