Where did the
money go?
Now you'll know.
Most months end with the same small worry. yen-yen takes that worry off your plate — quietly, in the background, on whatever phone is in your hand. By the end of week one you'll know where it went. By the end of month one, what you'd like to change.
Try it without an account. We never ask for your bank password, never run an ad, never keep you in if you'd rather leave.
Try the demo before signing up. Free for one person. $3 a month for the whole house, up to five.
- Conbini coffeeNeed−¥420
- Studio Ghibli bookCulture−¥2,640
- Lunch with MioWant−¥1,820
- Vet visit (Tama)Unexpected−¥6,500
- Salary (April)Income+¥420,000
Four tiny questions.
One honest portrait.
One small ask, when you log a spend: what was this for? Need, want, culture, unexpected. That's it. (The idea is borrowed from a 1904 Japanese household ledger, but you don't need to know any of that — the question works on its own.)
After a month, the answers stop being a list of receipts and start being a portrait of what you actually value. After three, the change you'd most like to make is usually obvious — and a lot smaller than you'd feared. Skip the question whenever; the ledger still works.
Rent, groceries, the bus pass — the things you can't opt out of without rearranging your life.
The Friday coffee, the new running shoes, the Saturday brunch. Joy, on purpose, no shame.
A book, a course, a museum ticket, money sent home. Spending that makes you a little more you.
The vet bill, the broken laptop, the surprise plane ticket. The reason emergency funds exist.
Most ramen is a want. Sometimes it's culture. Once a year, it's unexpected.
You're not getting graded. The point is the asking. The label your future self looks back on three months from now is the truth — and it's almost always more generous than you'd expect.
Five small worries
you can stop carrying.
The things our own households kept fighting about, quietly removed. Not a feature list — a list of evenings that won't end the way they used to.
"AMZN MKTPLC PMTS" → "Books, for Mio's birthday."
Paste the statement. Skim the result. Fix the two lines it misread. Tap save. The thing that used to take a Sunday afternoon is the time it takes to finish the coffee — and nothing is written until you nod.
04/22 STARBUCKS #34A2 -¥520 04/22 SUICA RECHARGE -¥2,000 04/23 KINOKUNIYA -¥1,840 04/23 SUSHI SAKURA -¥3,200
- WantStarbucks−¥520
- NeedSuica recharge−¥2,000
- CultureKinokuniya (books)−¥1,840
- WantSushi Sakura−¥3,200
"How much did I actually spend in Bangkok?"
Spend in baht on Tuesday, in yen on Friday — yen-yen remembers the rate from the day you spent, not today's. The number that comes back next year is the number you actually spent, not what the market thinks of it now.
Share the ledger. Skip the argument.
When you both look at the same numbers, the conversation gets shorter. Invite a partner, a parent, a roommate — everyone sees the same week, every edit is initialled, no one has to remember on whose phone the receipt lives.
Catches the receipt before it slips your mind.
The thirty seconds between the receipt and the next thing on your day are when most household ledgers go quietly wrong. yen-yen captures the line right then — signal or no signal — and reconciles later. The receipt never wins by attrition.
The day you'd rather leave, your data leaves with you.
Two taps for a CSV or QIF, two more to delete. Stored encrypted in a Tokyo Postgres database, walled off by row-level security so no other household — not even ours — can read your week. No ads, no data brokers, no sticky exit.
Free for one. Less than a coffee for the whole house.
The free ledger keeps working forever, on iPhone and Android, no card and no countdown. yen-yen Plus opens the household features for ¥450 a month — try it free for seven days.
If it's just you.
- The whole ledger — every account, every line, every currency.
- Your data, your phone — daily local backup, exportable in two taps.
- The four-question habit (or skip it; the ledger still works).
- No ads. No upsells in the menus. No trial countdown.
When the money is shared, the ledger should be too.
- Everyone in the house — up to five members on the same ledger.
- Paste-the-statement parsing — the half-hour chore turned into a coffee sip.
- Quiet roles — owner, contributor, viewer — so private things stay private.
- Longer audit retention and priority support, usually inside a day.
Subscription details
yen-yen Plus is an auto-renewing subscription billed monthly (¥450 / $2.99) or yearly (¥2,800 / $19.99). The first seven days are free; after that, your default payment method is charged at the start of each period. Renewal can be turned off at any time from your App Store, Google Play, or web billing portal at least 24 hours before the period ends — once turned off, access stays on through the end of the paid period. The free ledger keeps working forever whether or not you ever subscribe.
By subscribing you agree to our Terms of Use and Privacy Policy.
Running a small shop or studio that needs more than one workspace, deeper roles, or SSO? Tell us at kensaurus@gmail.com and we'll move the Team tier up the queue for you.
The questions we get asked the most.
01Do I have to give you my bank password?
Never — and please never give it to anyone who asks. yen-yen reads bank statements you paste in (a PDF, a CSV, or just the lines you copy from your banking app). Nothing is saved until you tap save.
02Will my partner see my therapist or my surprise gift?
Only what you choose to log to the shared household ledger. Each member also has a private workspace that only they can see. Use it for personal things; share what's actually shared.
03Where does my data actually live?
In a Postgres database in Tokyo, encrypted at rest, with row-level security so no other yen-yen user — and no other household — can read your rows. You can export the whole thing as CSV or QIF in two taps, and delete your account in two more.
04Does the AI see my whole bank account?
Only the lines you paste, only at the moment you paste them. It doesn't see your balance, your other accounts, or anything you didn't hand it. We log how much each parse cost so you can audit it yourself in Settings.
05We've been arguing about money for years. Will an app fix that?
Honestly, no app can. But most money fights start with one person not knowing where the money went, and yen-yen makes that part take ten minutes. The conversations that follow tend to be calmer when both people are looking at the same numbers.
06Why 'yen-yen' if I don't live in Japan?
Doubling a word is how friendly questions sound in Japanese — a soft "money, money?" whispered to yourself at the end of the month. The app speaks 27 currencies; use whichever ones fit your life.
07Will there ever be ads or upsells?
No ads, ever. yen-yen Plus (¥450/mo or ¥2,800/yr, 7-day free trial) covers household sharing, AI statement parsing, longer audit retention, and priority support. The free ledger keeps working forever whether or not you subscribe — we'd rather lose you to another budgeting app than serve you an ad next to your grocery line.
08How does the seven-day free trial work?
When you start yen-yen Plus you get the household features for seven days at no charge. You can cancel any time from your App Store, Google Play, or web billing portal — if you cancel before day seven, you're never billed. After the trial, ¥450 a month (or ¥2,800 a year, billed once) renews automatically until you turn it off. Once you turn renewal off, access stays on through the end of the paid period.
Try it before you sign up.
Install on your phone — the demo runs straight from the app icon. Log a coffee, watch the bar move. If it feels right, your real ledger is one tap away. If not, walk off with no email left behind.