Craft Commerce is a welcome addition to the Craft CMS ecosystem, offering native functionality for full-fledged e-commerce sites built right within the same powerful system we’ve grown to love. It currently offers product variants, discounts, coupons, customer address management, and detailed order customization, with recurring payments and memberships on the roadmap. As is the case with most e-commerce development, however, custom code is frequently necessary to accommodate specific business rules. This was the case with a project the ZC team has been working on.