Ever wondered what really happens when a Flutter app connects to a wearable that has been collecting data for hours? Getting the connection to work is the easy part. The interesting problems start when real data begins moving: connections fail, data arrives in unexpected ways, transfers get interrupted, and the same data can sometimes appear twice. Meanwhile, Flutter still has to keep the experience fast and responsive. In this lightning talk, we’ll go behind the scenes of a production Flutter wearable application and uncover the engineering decisions that make the whole experience reliable. Expect BLE, real-world failures, performance problems, and a few lessons that only become obvious after you’ve shipped. Because making BLE work is one thing. Making it reliable is another.