Penny Diary

Overview

Penny Diary is a personal finance tracker: a SwiftUI iPhone app and a Next.js web app that share one ledger. Every entry is typed, spoken, or tapped in by the person who spent it, with no bank connection, and the app reads it back as a clear picture of where the money went. The iPhone app works on its own with no account, and Penny Diary Pro syncs the ledger to the web and across devices.

Features

• Where It Went - Home shows the period's spending as one large figure against the period before, twelve periods of history, and the categories that took the most, with their share and trend

• Fast Entry - An Add sheet one tap away on every screen, fill-in by voice, title suggestions that bring their amount and category with them, and an Add Transaction action for Siri, Spotlight, and Shortcuts

• Apple Pay Automation - A Shortcuts automation records each Apple Pay purchase as it happens, cleans up the merchant name, and marks the entry as automatic

• Reports - Spending and income by category in a share ring, day-by-day bars, insights, and saved reports for the views that matter, such as food or fixed costs

• Recurring Entries - Weekly, monthly, and yearly rules for rent, pay, and subscriptions, which write each entry on its due date, with what the next 30 days will bring

• Refunds and Adjustments - A return or cashback is recorded against the purchase it belongs to, so the original amount stays on record and reports count what was really spent

• A Desk-Sized Web App - The same ledger in a wide layout with a sidebar, side panels, and keyboard shortcuts for every common action, plus CSV export

• The Ledger Look - A paper and ink design system in light Paper and dark Navy themes, built once and shared by both apps

Responsibilities

• Designed and built the whole product alone, from the design system and both apps to the database, the subscription, and the App Store release plan

• Built the iPhone app in SwiftUI as local-first: the ledger lives on the device and works offline, and a write queue syncs it to Supabase once the person signs in, recovering from refusals, conflicts, and lost answers without losing an entry

• Built the web app with Next.js, React, TypeScript, and Tailwind CSS, deployed on Vercel, with every tab loading on the client so moving around the ledger never waits on the server

• Designed the shared PostgreSQL schema in migrations, with row level security on every table, decimal amounts the database adds up itself, soft deletes with a recently deleted list, and SQL tests run against a fresh database

• Kept every report number identical on both clients by mirroring the report logic in Swift and TypeScript and holding both to one shared parity fixture

• Built Penny Diary Pro with StoreKit 2 and Supabase Edge Functions that record subscriptions from data Apple signed, so a purchase on the iPhone unlocks the web for the same account

• Added Sign in with Apple and Google, a Face ID app lock, a daily logging reminder, a ledger currency chosen from the world's currencies, and a privacy policy that tests hold to every column the database stores

Screenshots