StoreZed

The problem

Merchants were reconciling sales against payouts by hand. Balances drifted because the wallet was a single number on a user row, updated from several places.

What I built

I replaced the balance column with a double-entry ledger. Every movement of money is two rows that must sum to zero, and a wallet balance is simply a query over those rows.

def transfer(debit: Account, credit: Account, amount: Decimal, ref: str) -> None:
    with db.transaction():
        Entry.create(account=debit, amount=-amount, reference=ref)
        Entry.create(account=credit, amount=amount, reference=ref)

• Idempotent payment webhooks keyed on the provider reference
• Payouts queued and retried with backoff, never fired twice
• Daily reconciliation report comparing the ledger with the payment provider

Outcome

Support tickets about missing money stopped. Finance could close the month from one report instead of three spreadsheets.