01 — The problem

Transaction volume had outgrown a ledger that was never designed to be one. Reconciliation ran overnight, broke often, and every break required a human to trace a payment across four systems.

02 — The system

We rebuilt the money layer as a strict double-entry ledger with idempotent transaction ingestion, then automated reconciliation against provider and bank statements.

03 — The build

Go services behind an API gateway, Kafka for transaction streams, PostgreSQL for the ledger of record, and a monitoring console that surfaces breaks as exceptions rather than as a nightly report.