Looking for a Flutter solution for background/killed app notifications based on proximity

Hey devs! 👋

I’m planning to build a Flutter app with two sides: a sender and a potential receiver. The receiver could have the app open, in the background, or even killed.

The idea is:

When the sender sends a request, the app checks if the receiver is nearby (within 50 km).

If they are, the receiver gets a notification like: “Someone nearby sent a request.”

Ideally, it would also know the receiver’s location relative to the sender, but that’s optional.

I’m aware that iOS and Android have strict background/killed app restrictions, so I’m looking for a reliable, cross-platform solution. If it only works on one platform, that’s fine too.

If anyone has experience with:

Background location tracking in Flutter

Sending notifications from killed apps

Proximity-based triggers

…please share your approach or any guidance. Really appreciate it! 🙏