How it's built

Screens

Tech stack

• React Native + Expo iOS-first, TypeScript throughout, built on Expo SDK 54 — around 28 screens covering the garden, lessons, pets, shop, and social features.
• On-device speech recognition A quantized ONNX speech model runs entirely on the phone via WebAssembly, so your voice never leaves the device. A custom tone gate checks the phrase against the expected Cantonese tone contour.
• Supabase backend Postgres and Auth handle accounts and sync, with server-side Postgres functions for anything that needs to be tamper-resistant — like reward and pet outcomes — instead of trusting the client.
• Local-first sync Progress renders instantly from on-device storage and syncs to the backend in the background, so the app stays fast and usable even on a spotty connection.
• Content pipeline Close to 1,100 phrases across 29 lessons, authored once and compiled into a static bundle shipped with the app — lessons load instantly with no server round-trip.
• Self-hosted beta distribution This very beta runs on a small self-managed Oracle Cloud VM serving the Expo Metro bundler directly, so testers get the latest build over the network without waiting on App Store review.