Finthemis

Budget by rules, not categories.

Most budget apps reset every month. Mine doesn't. Overspend in March and April's allowance shrinks. Underspend and it banks. The balance has memory.

I'm Alex, an iOS engineer in Romania. For the last year I've tracked my spending in a Numbers spreadsheet using a rule I made up: entertainment spending capped at 4% of my net worth, applied monthly, with the balance rolling forward.

It works better than any budgeting app I've tried, but maintaining it in a spreadsheet is painful. So I built the app I wanted.

Finthemis is launching soon. Drop your email if you want to know when.

What's in the app:

• Rules that constrain spending by category (e.g., "Entertainment ≤ 4% of net worth, monthly")
• Rolling balances, overspending and underspending carry across periods
• Your data lives in CSV and JSON files you own, editable in any spreadsheet
• Lock-screen widget showing your current available balance
• No accounts, no logins, no ads, no tracking