Open Source TypeScript Financial Calculators

zero is a privacy-first, fully offline expense tracking app for Android and iOS. Unlike most finance apps, zero does not require accounts, cloud sync, subscriptions, or internet access. All financial data stays locally on your device. There are no ads, no telemetry, and no analytics. zero helps you: • Track daily expenses in a clean timeline • Visualize spending with simple reports • Create unlimited custom categories • Manage lendings and borrowings • Export or delete your data anytime Built with a local-first philosophy, zero gives you full control over your financial data. Your data. Your device. Zero servers. Open source and actively maintained.