When I decided to build Pairio , an app that securely mirrors notifications between two Android devices, I knew the technical requirements would be steep. The app needed to intercept notifications in real-time on one device, instantly transmit them to a paired device, and run continuously in the background without being killed by Android's aggressive battery optimizations. Most importantly, it had to be 100% private and secure with zero data retention. Here’s a deep dive into the arc...