Building a consumer AI app right now is wild. Building one that relies on biometric data? That adds a massive layer of complexity, especially when you want to ensure total user privacy. Most "lookalike" apps out there rely on creepy web scrapers or basic reverse image searches. I wanted to build something entirely different: a 100% closed, opt-in biometric network where the user owns their face data. So, I built DopplGrid. Here is a look at the stack and the architecture behind it. The Stack & Architecture I wanted to get the web application running flawlessly before wrapping it for the native iOS and Android releases. The frontend is built in React and heavily styled with Tailwind CSS to keep the UI clean, fast, and responsive across devices. For the backend and secure data vault, I am relying on Firebase. The core of the app is a biometric matching engine. Instead of scanning colors or pixels, it maps 128 unique points of a user's facial geometry.…