Project
Tally — an offline credit ledger for small merchants
A record of debts and credits that replaces the paper ledger but, like a paper ledger, never leaves the shop.
The problem
Small merchants still track what customers owe them in a paper ledger — who pays when gets forgotten, reminders are done by hand, and there is no backup at all.
The solution
A ledger app that runs entirely on the device, with no data going to any server. Due-date reminders can be set per customer (3 days, 1 week, 2 weeks or 1 month ahead), and once a date passes, a reminder goes out over WhatsApp with one tap. CSV/JSON backups and a biometric lock are included.
The "no server" decision is not a gap but this product's selling point. What customers owe a merchant is sensitive data; every step like creating an account, signing up or syncing to the cloud raised both the trust barrier and the effort to get started. I tied the need for backups not to a cloud but to a CSV/JSON file in the user's own hands.
Technology
A detail worth highlighting
The report screen automatically compares this month with the last and pulls out the five largest balances — answering the merchant's question "who owes me how much right now" without going through the ledger entry by entry.
Let's talk about a similar problem
If you have a product that has to be designed for real conditions in the field — no internet, one hand, in a hurry — write to me.