SubSub — Hackathon Submission

Inspiration

Subscriptions renew while you're not looking — and most trackers want your bank login or charge a monthly fee to track the monthly fees. I built SubSub after using Bobby and hitting its limits: no Mac app, shaky sync elsewhere (ReSubs), and no good option for people who manage renewals in Notes or spreadsheets but want something private and reliable.

What it does

SubSub is a privacy-first subscription tracker for iPhone and Mac. Add services manually (no bank linking), see monthly and yearly spend, get renewal and trial reminders, and know what's coming before it charges. Data stays on your device by default; iCloud sync is optional. One-time purchase — no subscription to track subscriptions.

How I built it

Native SwiftUI app with SwiftData for local storage and optional CloudKit sync across iPhone and Mac. Built the core offline-first, then layered sync, StoreKit one-time unlock, local notifications, and a marketing site at subsub.app. Shipped dual-platform from one codebase with platform-specific layouts.

Challenges I ran into

Making optional iCloud sync reliable across iPhone and Mac — competitors get this wrong. Competing against established apps (Bobby) without copying their tradeoffs. Building a Mac app as a real differentiator, not an afterthought. App Store review, sandbox IAP, and dual-target Xcode setup added real shipping friction.

Accomplishments that I'm proud of

Shipped a real App Store product that solves gaps from App Store research: Mac support, privacy-by-default, one-time pricing, sync you opt into. Rock-solid local-first architecture with extensive sync tests. From idea.md research to live app — "see every charge before it hits."

What I learned

Privacy is a feature, not a footnote — users will manually enter subs if you don't sell their data. Offline-first simplifies everything; sync becomes an upgrade, not a dependency. One-time pricing resonates when your app literally tracks recurring charges. App Store research beats guessing what people want.

What's next for SubSub

Home screen widgets for upcoming bills, categories and better organization, price-change history, optional on-device screenshot scanning, and richer customization (icons, colors, paused subscriptions). Keep the focus: simple, private, reliable — no feature bloat.

Built With

• swift