A customer credit (“tab”) ledger for a corner shop — offline, no monthly fee
The notebook never asked for a login. A plain-words guide to replacing it: the four fields, the two rules, how to move the old tabs across, and how to settle up without awkwardness.
Leanfinit · 6 min read
Every corner shop has the notebook: names down the side, amounts scribbled, lines crossed out when someone pays. It works because it is fast and private. It fails because it gets wet, it does not add up on its own, and when the owner is off sick nobody else can read the handwriting. The “credit apps” in the store ask for a business login, a connection, and after thirty days a monthly fee. This guide shows how to describe a replacement that keeps what the notebook does right, and how to actually switch — including the part where you tell Mrs Okafor what she owes.
What the notebook does right (keep all of it)
The four fields and the two rules
Resist adding more. A tab ledger is customer, amount, date, and a short note. Everything else — categories, receipts, interest — belongs in an accounting tool you will never open at the counter.
| Field / rule | What it is | Why it matters |
|---|---|---|
| Customer | A name you recognise: “Dave (garage)”, not a customer ID | You search by name while they wait |
| Amount | Positive for a purchase, negative or “payment” for money received | The balance is just the sum |
| Date | Set automatically | Needed for the two rules below |
| Note | “2 bread, milk” — optional | Settles “what was that for?” in a second |
| Rule 1 — limit | Red when a balance passes your limit (say 50) | You see it before you say yes to the next item |
| Rule 2 — age | Amber when the oldest unpaid line is over 30 days | The polite nudge happens before it is awkward |
Step 1 — Describe it
“A customer credit ledger for my shop. Customers list with balance, sorted by largest first; red if over 50, amber if the oldest unpaid line is older than 30 days. Tap a customer: their lines (date, amount, note) and a big “add” button with a numeric keypad; a “payment” button that subtracts. Add a new customer with just a name. Monthly total of credit given and received. Works offline, no account. Export everything as a text file.”
Step 2 — Move the notebook across (one quiet evening)
- 1Enter balances, not historyFor each name, one line: today’s date, the current balance, note “from notebook”. Do not retype three years of lines.
- 2Keep the notebook for two weeksWrite in both. Compare on Sunday. If they match twice, retire the notebook to a drawer — do not throw it away yet.
- 3Add the regulars firstThe ten people who come daily are 80% of the lines. Enter them at the counter, when they are standing there, and confirm the balance with them. That conversation is the migration.
Step 3 — Settling up without awkwardness
The amber rule does most of the work: you see the 30-day mark before they do, and “you’re at forty-one days, shall we clear some of that?” is easier when the number is on a screen rather than in your memory. Keep payments as lines too, not as edits — a tab that shows “paid 20 on the 12th” settles disputes; a balance that mysteriously changed does not.
If someone else runs the till
A device-only app lives on one phone. That is a feature for privacy and a limitation when two people serve. The practical fix is simple: the ledger lives on the shop’s phone, not yours, and stays by the till. If you really need two devices, describe a daily export that you share by message — and accept that a true live sync means a server, and a server means a fee.
Changing it later
The first change most shops ask for after a month is a “frequent items” row — bread, milk, cigarettes — so the amount is one tap. The second is a monthly statement per customer to show them. Both are one sentence to describe. Your lines stay; the app around them changes.
- Describe
- Enter balances
- Run both for 2 weeks
- Retire the notebook
Describe your own app →
Takes a few sentences. Private, yours.