1. BillingBase Developer Overview

Billing affects revenue and customer balances. Keep changes focused and add scenario-level tests.

1.1. Module responsibilities

modules/BillingBase contains billing configuration, products/items, taxes, accounting records, SEPA data, settlement runs, invoices, and related jobs/commands.

1.2. Important areas

Entities/SettlementRun.php and settlement jobs/commands
Entities/Invoice.php, Item.php, and AccountingRecord.php
notification, invoice-generation, export, and archive jobs
module Feature/Lifecycle tests

1.3. Contributor guidance

Use decimal/money-safe representations already established by the module
Preserve accounting traceability and idempotency
Queue long-running settlement/invoice work
Restart queue workers after deploying changed job code through the supported service workflow
Test calculations, retries, permissions, and customer-visible output

Operator procedures belong in the Billing application documentation; this page is for source orientation.