case study

Tendere

Founder and full stack engineer: Expo, local-first sync, auth

problem: Recurring chores and bills are easy to miss. Shared household lists usually force an account and a network before the app is useful.
outcome: A shipped iOS app: Solo Mode stores tasks on-device with local notifications. Duo Mode adds email OTP auth and selective sync for one invited group.
ownership: Designed and implemented the Expo app, Today list, reminder scheduling, and Settings.
Built Duo Mode: Supabase Auth (OTP), group invite codes, and PowerSync for offline-capable partner sync.
Published App Store support, privacy, and marketing pages on olamide.dev for review and users.
architecture: Local-first SQLite on device. Solo Mode never leaves the phone.
Duo Mode: Supabase for accounts and shared rows; PowerSync connector to replicate only reminders marked shared.
Local notifications via expo-notifications using title and schedule stored on device, so Solo needs no push service.
Turning Duo off signs out, stops sync, and returns the user’s own data to the device.
trade-offs: One Duo group at a time to keep sync conflict rules simple for a household product.
Passwordless OTP instead of passwords: fewer secrets on device, one extra email step for reviewers.
No ads or analytics SDKs so the privacy story matches the product: no tracking across apps.
stack: TypeScript · Expo · React Native · Supabase · PowerSync · SQLite
live: Product site