Koin lets you set a budget, log every expense, and watch your balance in real time — all in one clean interface.
Features
A focused set of tools built around one goal: knowing exactly where your money goes.
Budget Tracking
Define your total funds over a custom timeframe. Daily and weekly limits are calculated automatically so you always know where you stand.
Expense Analytics
Visualize your spending with line charts that show your balance depletion over time and highlight spikes before they become problems.
Color-Coded Categories
Tag every expense — rent, car, utilities, or everyday items — with a distinct color. Spot your biggest cost drivers at a glance.
Secure by Default
Firebase Authentication keeps your data private. Every API call is verified server-side before any data is touched.
Retroactive Entries
Forgot to log something? Use the date/time picker to add past expenses and let Koin recalculate your balance history automatically.
Real-Time Sync
Built on Firebase Realtime Database — your data updates instantly across every session, no refresh required.
By the numbers
Open the app, set your first budget, and take back control of your finances in minutes.
Open Koin