Finance & Double-Entry Accounting

Accounting isn't a payments log bolted onto billing — it's a physically separate double-entry microservice with a real ledger (accounts, transactions, journal lines, periods). Every business event — a bill, payment, expense, payroll run, bandwidth purchase, reseller funding — produces a balanced journal where debits must equal credits, validated before it's ever posted.

The hard part is resilience across 1,600+ tenants, and this is the moat: if the accounting service is ever offline, the posting isn't lost. Each failure is written durably to a per-tenant queue and re-driven by a Hangfire job with exponential backoff (5 min → 20 min → 1 hr → 4 hr → 12 hr). It's event-driven, so there's zero overhead when accounting is healthy — and the core billing or payment operation is never blocked by an accounting hiccup. Chart-of-accounts resolve by string identifiers, so the same journal logic fits every tenant's custom account structure, and each payment method (bKash, Nagad, ShurjoPay, bank) routes to its own GL account.