The premise

Most "cross-platform" stories stop at the pitch. RippleUp is a shipping product: v5.3.3 in production , distributed as an Android APK and a self-contained Windows desktop app, built with Kotlin, Jetpack Compose, and Compose Multiplatform 1.6.11 .

What the app does

RippleUp is a social-engagement platform: users self-report activities (with a 5-minute camera verification window), scan partner QR codes (live CameraX + MLKit barcode scanning), earn points and badges, and join events. Anti-abuse is built in — per-action cooldowns (45/30/90/120 min), 12 actions/day, 300 points/day.

The production backend

The cloud layer is a full Supabase setup: user accounts, sync, QR verification with location proof (who + where + map) , admin review, badges, notifications, and event registration.…