Technology

Last updated: 9 July 2026

Short version: TapXpense is local-first. The iPhone app uses on-device storage as the source of truth, supports guest use without an account, and only syncs when you choose to sign in.

Local-First App Data

Expenses, categories, accounts, budgets, subscriptions, and reports are stored locally on your device with SwiftData. The app is designed to keep working when you have no account and no network connection.

Optional Sync

When you sign in with Apple or Google, TapXpense can back up and sync your data through Supabase. Database rows are isolated per user with row-level security so one account cannot read another account's private data.

Fast Logging

Back Tap, widgets, Siri, and Shortcuts are built around App Intents so logging can start outside the app. The goal is to reduce friction at the moment you spend money.

AI Categorisation

Categorisation runs on-device where supported. If a cloud fallback is needed, it sends only the short phrase you typed for categorisation, not your full expense history or account identity.

Community Board

The website community board uses Supabase with row-level security. Public visitors can read ideas, submit pending ideas, and vote through a limited database function. It is separate from private in-app expense data.