yen-yen: Kakeibo Budget App

A kakeibo budget app and expense tracker for couples and households. See where your money goes, without giving any app your bank login.

· Log an expense in seconds: type the amount, tag it, save.
· See your week at a glance in four spending types, not fifty categories.
· Track cash, bank, card and loan accounts in any currency, with historical exchange rates.
· Stay on plan with monthly budgets, bill reminders and photo receipts.
· Keep your data yours: CSV / JSON import and export. Delete the account from the bottom of Settings; you can cancel for 14 days.


How it works

1. Type what you spent and hit save. No bank connection, no auto-categorization that gets it wrong.
2. Tag it with one tap: something you needed, something you wanted, something that feeds your mind or soul, or something you didn't see coming.
3. At the end of the week, see your pattern and decide what to change.

That four-bucket method is called kakeibo (家計簿). Japanese households have used it since 1904. yen-yen puts it on your phone.


Free, with optional add-ons

The solo ledger is free forever. No ads, and we don't sell your data.

Founder Cohort:
· Share a household ledger with a partner or roommate.
· AI-assisted statement import — paste lines, you approve every row, nothing auto-saves.
· Ask, longer audit history, and priority support.

The first 100 signed-up households get these Family features free (Founder access), with nothing to buy. After that, Pro and Family are optional in-app subscriptions, each with a 7-day free trial. The free solo ledger works forever whether or not you were in the cohort.


What yen-yen will never do

· Connect to your bank.
· Auto-write anything to your ledger.
· Send spending-guilt notifications.
· Show ads.


Account deletion

From the bottom of Settings. You can cancel for 14 days. Also at https://kensaur.us/yen-yen/account/delete.


Privacy

Hosted on Supabase (Postgres), encrypted in transit and at rest.

Privacy policy (web): https://kensaur.us/yen-yen/privacy
Terms (web): https://kensaur.us/yen-yen/terms
In-app (mobile): Settings → Help & legal → Privacy / Terms

Made by kensaurus LLC in Tokyo. Bugs and questions: [email protected]

One of a family of small apps — no sign-up wall. One optional account works in all of them.