React Native + Rails synchronization with WatermelonDB

I still remember the Slack message that changed my entire approach to mobile development. It came from our lead iOS engineer at 11:47 PM: “The app crashes when the train goes into the tunnel. Every. Single. Time.” We had built a beautiful React Native app for field technicians. The Rails backend was solid. The API was RESTful. The UI was pixel‑perfect. But the moment the network got spotty—on the subway, in a basement, in the middle of nowhere—the app fell apart. Spinners that never stopped. Forms that failed to submit. Users who wanted to throw their phones into the nearest river. We tried caching. We tried Redux persist. We tried local storage hacks. Nothing worked reliably. The app was a house of cards, and every network hiccup was a gust of wind. That’s when I stumbled on a GitHub repository with a strange name: WatermelonDB. I read the README, and my heart started racing. This wasn’t another “just store some JSON in AsyncStorage” library. This was a full‑blown, reactive database f