Independent product · Personal finance
Sine
A subscription tracker that never asks for your bank login.
Sine tracks renewals, free trials, price changes, and UPI AutoPay mandates. It reads billing messages on device, syncs through iCloud, and uses a one-time purchase.
- Role
- Product design · iOS engineering · Release
- Platform
- iPhone · iPad · iOS 26+
- Stack
- SwiftUI · SwiftData · CloudKit · On-device AI
- Released
- App Store · 2026
The product problem
Subscriptions are easy to start and easy to forget.
The expensive charge is usually the one you forgot: a trial conversion, an annual renewal, or a quiet price increase.
Sine avoids bank linking, accounts, analytics, and ads. It knows only what you add or import on device.
Getting data in
Recognition beats recollection.
A billing message or receipt screenshot already contains the service, amount, and date.
Sine turns that information into a draft subscription for review. Nothing is uploaded to parse it.
Time is the actual product
Being told after the charge is useless.
Every useful thing Sine does happens before money moves, which meant the app is really a scheduling problem wearing a finance interface.
See the month coming
A calendar and timeline of what renews when, with notifications far enough ahead to actually act on.
Cancel before it converts
Free trials are tracked separately and warn ahead of the conversion date, which is the only moment the warning is worth anything.
Notice the creep
Cost changes are recorded over time, so a service that has quietly doubled is visible instead of merely annoying.
Burn rate, not a ledger
Monthly and annual totals with category breakdowns and multi-currency support. Enough to decide, not enough to become a spreadsheet.
India
UPI AutoPay is a subscription the West's trackers cannot see.
A large share of recurring payments here run on UPI AutoPay mandates, which behave differently from card subscriptions and are invisible to tools built around Western billing.
Sine tracks mandates as first-class objects. The payment systems case study covers failed captures after authorization.
Outcome
Shipped, private, and not itself a subscription.
Sine is live on the App Store for iPhone and iPad. It has private iCloud sync, widgets, Lock Screen support, Siri, Spotlight, reminders, export, and a one-time purchase.