FCM said sent. The phone was in a drawer.

transcript

A fraud alert goes out. FCM says: sent. Your dashboard says delivered. Did Priya ever see it? The phone has been in a drawer for three days.

The platform sends a fraud alert to Priya's phone. FCM accepts it, and hands back a message ID. So it's delivered. Right?

You'd assume sent means it reached the phone. Here's the catch. FCM counts a send when it's enqueued. Receipt comes later, from the app or FCM's delivery data. Here, it never comes.

So the delivery row says sent. Not delivered. Delivered waits for the device itself. It doesn't count toward 99.9 percent. Measure the gap. Email too. An accepted email can still bounce an hour later.

So push alone can't carry a critical alert. Still unread after 2 minutes? It escalates to SMS. Any phone, no app needed. One notification. Two deliveries. Each with its own status.

A provider's yes only means it took the message. Not that anyone saw it.

Full breakdown in the lecture.