Kaasu: a spending diary you talk to
Kaasu (காசு) means money in Tamil. Say "700 for groceries on Zepto", "ezhunooru auto, cash", or share a bank SMS. Kaasu files it and tells you where your money went. I designed and built it end to end with Claude, and I use it every day.
Use it right here.
This is the real app, running in a phone frame. Tap the mic and say a spend, tap Type, or press Load a sample week to see the summaries.
Your entries stay in your browser. Voice needs Chrome or Safari and mic permission.
One thumb, three tabs, one mic.
Tracking fails at the moment of spending.
Every expense app I tried died the same way: I paid ₹60 for chai in cash, meant to log it later, and never did.
Apps either read your inbox or make you fill forms.
I compared the trackers people in India use today. Digital payments are well covered. Cash, still an estimated 50 to 60% of household spending (RBI, Oct 2024), is not.
| App | How you log | Good at | Falls short |
|---|---|---|---|
| Axio (was Walnut) | Reads bank SMS | Automatic for UPI and cards | Needs SMS access. Misses cash. |
| Money View | Reads bank SMS | Budgets, bill reminders | SMS access can expose OTPs |
| Money Manager | Manual forms | Fine control | 30 to 60 s per entry |
| Jupiter, Fi | Linked bank | Auto categories | Must link or move your bank |
| Finny | Voice, text, receipts | Fast capture | iOS only. AI is paid. |
| Kaasu | Voice, shared SMS, or payment alerts you confirm | Cash in one sentence, no account, no inbox access | Auto-log is Android only, installed from my site |
Sources: RBI Monthly Bulletin via Data For India, Finny and Calcwise app reviews (2026), store listings.
Talk like you'd tell a friend.
Every other app
Kaasu
- Save first, fix later. Instant save with Undo and Edit, no confirm screen.
- Private by default. No account, no bank linking. Data stays on the phone.
Each change came from using it.
Prove one sentence works
Mic, typed text and pasted SMS into one on-phone parser. Plain-word summaries. No account.
Build the habit, test with my dad
Opens on Today, tap tags, Undo instead of confirm. In my dad's test the mic cut him off mid-sentence, so it now listens until you tap Done.
Speak your language
Tamil and Hindi number words and script, mishearings like “outer” for auto. The form fills in as you talk, and you can say several spends in one go.
Any day, any month
Say the date (“31st October”, “last month”). Open any month since your first entry. A streak and an evening nudge.
It logs itself
I skipped logging for two days. A helper app made alerts open Kaasu, but setup took me an hour. So Kaasu became an Android app that reads bank SMS itself.
Transfers and UPI Lite
Money moved between my own accounts showed up as spend and income, so Kaasu now pairs them and asks once. UPI Lite sends no SMS, so Kaasu checks each Lite refill. Your own categories too.
“Show me tags that I can click and add to the text box, and ask me for confirmation before I delete anything.” My own note after using version 1.
Built with AI. Decided by me.
Built for how India talks about money.
No AI service and no network call. A small rule-based parser runs on the phone, so it's instant and private. Pick English, தமிழ் or हिंदी right by the mic.
1.2 lakh salary→
ezhunooru auto, cash→
do sau ka chai→
Swiggy 480 yesterday→
Rs.649 debited … VPA blinkit.payu@hdfcbank→
Tested on spoken phrases and real-format HDFC and UPI messages. Ignores account and card numbers.
Pay anywhere. Confirm in one tap.
Typing every spend is the habit people drop first. So Kaasu now listens for the payment alert your phone already gets.
- Your own money moving is not spending. Same amount out of one account and into another: Kaasu asks once, “₹12 moved between your accounts?” It also learns your name from those messages, so a one-sided message like a UPI Lite payment to your own account is caught too.
- UPI Lite. It sends no SMS per payment, only when it refills. Kaasu subtracts the Lite spends you logged and asks about the rest.
- Wallets. Amazon Pay balance payments arrive by SMS. Paytm wallet payments send nothing, so a weekly wallet check asks for your balance and shows what is missing. Money added to a wallet counts as moved, not spent.
- Cards. Card purchases come from the bank SMS, marked Paid by Card.
- Confirm here, unlike voice. Alerts include self transfers and wallet top-ups, so a wrong guess costs more than one tap.
- Never guess the amount. If an alert has no ₹, Rs or INR, the amount box stays empty.
- No inbox access. Kaasu reads only the alert it is handed, on your phone.
Testing took longer than building. Banks and payment apps only show how they behave when real money moves: which ones send an SMS, which stay silent, how late an SMS arrives, how they word it. So I checked every rule with ₹1 to ₹12 payments on my own phone, across bank accounts, my own transfers, UPI Lite and wallets. One idea failed outright: reading Paytm's success screen made Paytm block payments, so I removed it.
Android only: iPhone apps cannot read SMS.
Small choices that make it fast.
A mic in the thumb zone
A dock at the bottom: Type, a big mic, and Paste SMS.
Undo, not "Are you sure?"
Saves instantly with Undo or Edit. Only delete asks first.
Insights in plain words
"2 app orders came to ₹1,180." Monthly budgets warn at 80%. An evening nudge if no cash was logged.
Real people, real spends, seven days.
- Time to log cash: stopwatch, tap to saved. Goal: median under 3 seconds.
- Parser accuracy: share of entries saved without an edit. Goal: 85%.
- Habit: testers still logging on day 7. Goal: 6 in 10.
- Ease: SUS survey. Goal: 70 or more.
Want to be a tester? Message me on WhatsApp. Results go here when the test ends, good or bad.
Honest about what's missing.
Can't do yet
- 🌐Voice needs internet and Chrome or Safari.
- 📵No sync. One phone, one browser. Export a CSV.
- 🔌Auto-log is Android only, installed from my site for now. iPhone cannot read SMS.
Next
- ⚡Save from the notification, without opening the app.
- 🔒Quick Settings tile to log cash from the lock screen.
- 🗣️Full Tamil and Hindi sentences, and push reminders.
- ▶️Play Store release.