Billwerk+
payment and subscription plugins for WooCommerce
I maintained the WordPress payment gateway and built a separate subscription integration, with refactoring and PHPUnit tests.
- Field
- Payments and subscriptions
- Built with
- WordPress / WooCommerce / PHP
- Project year
- 2022–2024
The challenge
WooCommerce merchants needed Billwerk+ payment and recurring-billing functions inside their stores. The existing gateway also required a more maintainable codebase so new capabilities could be added with greater confidence.
The approach
The engagement covered the existing payment gateway and a separate subscription integration. Refactoring followed WordPress conventions, with PHPUnit tests supporting changes to payment-related behaviour.
The project, in detail
The images show the interface and its context. Captions distinguish project archives from current-site views.
The gateway’s role
The gateway exposes payment methods supported by Billwerk+ and connects recurring charges to WooCommerce Subscriptions. The work extended an existing plugin rather than replacing the merchant’s commerce platform.
Subscriptions across storefronts
A separate plugin connects the Billwerk+ Subscriptions API to WooCommerce. Subscription information is held in Billwerk+ administration, giving merchants a shared subscription layer across more than one storefront.
Maintaining financial behaviour
Refactoring and unit tests address the cost of changing inherited code. Later work prioritised the main gateway and its compatibility with WooCommerce Subscriptions; the two plugins did not receive identical development priorities.
The outcome
Payment-gateway improvements and a dedicated Billwerk+ subscription integration backed by automated tests.
Details of Billwerk+
Were the payment gateway and subscription layer one plugin?
No. The existing gateway was refactored and tested, while a separate plugin connected the Billwerk+ Subscriptions API to WooCommerce.