Building the Family Bank, a Kid's Allowance Ledger
Instead of just handing over allowance, I wanted my kids to record it, see the balance, and spend within it — so I built a double-entry ledger.
When I started giving my kids an allowance, one thing bothered me. Money shouldn't be something that just appears and vanishes. How much allowance and errand money has piled up, how much is there right now when you want to spend, and the sense of spending only within that amount — I wanted them to absorb that early, through experience. We tried a paper allowance notebook, but it never lasted. So I decided to build a small ledger app shaped for our own house.
Like a bank, but family-sized
The structure is simple. Money that comes in — allowance, errand money — and money that goes out gets recorded as it happens. A child sees their current balance at a glance on their own screen, and can only spend within it. As the entries pile up, they start looking back at where their money went — which, honestly, is the real purpose of the app. The habit matters more than the balance.
One fun feature: leaving spare money on deposit with a parent. Money you're not going to spend right away goes into the 'family bank.' To a kid it feels like playing bank, but it's a natural first encounter with the idea of saving. It's also how the app got its name.
A ledger is serious business, so: double-entry
The part I sweated over most was, surprisingly, the accounting structure. Entries will get edited or deleted — a typo, a cancelled errand. If you build it as simple adding and subtracting, a few overlapping edits and the balance quietly drifts. And if the balance a child sees is wrong, the tool loses their trust and it's over. So I built it on double-entry bookkeeping, the way real accounting works. Every record is a debit-credit pair, so editing or deleting entries never breaks the balance of the ledger as a whole.
Login is delegated to a family account. Instead of creating separate accounts for each child, everyone lives under one family login, and each child gets their own ledger inside it. The kids don't have to manage passwords, which is what fits our house.
Where it stands
It's finished and our family actually uses it. I've even prepared deployment docs so another family could spin up their own. How far — and how — to open it up is still an open question. It's a tool that holds a child's money records, so I want to be careful about going public.