Building a Double-Entry Ledger System in Laravel

Every financial platform needs a reliable ledger. At KmarApp, we built our double-entry ledger system on top of Laravel using several key database and application patterns.

Atomic Transactions

Every financial operation at KmarApp runs inside a database transaction. If any part of the operation fails, the entire transaction is rolled back. This ensures that money is never created or destroyed by a partial failure.

Row-Level Locking

We use SELECT ... FOR UPDATE to lock wallet rows during balance operations. This prevents race conditions where two concurrent requests could both read the same balance and produce incorrect results.

Event Sourcing

Every balance change is recorded as an immutable event. This gives us a complete audit trail for every transaction, from creation to settlement.