| billing | Includes enums for payment methods and transaction statuses, interfaces for billing transactions and receipts, and services to process transactions, manage billing history, and generate receipts. |
| customer | This module contains types and services related to customer management. |
| products | This module contains types and services related to product management. |
| shipping | This module contains types and services related to shipping. It includes definitions for shipping records and services to manage the logistics of shipping orders. |
| utilities | This module contains generic utility functions useful for various operations. |