Basics - Integration

Sandbox Server

Before diving into technical details, sign up for a free sandbox account. The sandbox represents a test system entirely independent of our live servers. It can be used for any evaluation and integration processes.

Customer Self Service

Primarily, integration means adding Billwerk+ Transform functionality to your customer self-service pages:

  • Public signup/order process: Accessible publicly for new customers.
  • Restricted Customer Portal: Any change for existing customers, be it an upgrade, a cancellation, or just modifying some customer data such as the email address.

There are two approaches to integrating Billwerk+ Transform into your customer self-service: seamless and flexible integration with SubscriptionJS or Hosted Pages.


SubscriptionJS is a JavaScript SDK for seamless integration and full customization of your customer self-service pages. The SDK provides a simple, yet flexible interface to Billwerk+ Transform that covers use cases for signup and customer portal.


Hosted Customer Self-Service

Billwerk+ Transform provides hosted pages for Signup and Customer Portal. Integration requires minimal effort and coding skills, but customization is limited.

Hosted Customer Self-Service

How to Choose

Choosing between hosted self-service and the SubscriptionJS approach can be challenging. Consider your customization requirements and the features you need.

How to Choose

No Customer Self-Service required?

If customers sign up with you directly, or they don't sign up online at all, for instance, if you sell subscriptions via phone, or you want to bill existing customers, you can skip integration completely. You can manage subscriptions manually using the Billwerk+ Transform Admin UI. This 'no-self-service' approach is straightforward if you handle mostly direct debit and invoice payments. Suppose you also want to support credit card, PayPal or Skrill payments. In that case, you can still send customers to a page where they can enter their payment information secretly and without any PCI DSS certification problems. Still, you might want to connect to the API to create customers and contracts in Billwerk+ Transform automatically so they'll be billed automatically.


You can test your code using the billwerk Sandbox without hitting the live system and potentially messing up your live account. The Sandbox is located at, the corresponding API URLs start with The sandbox and the live system are not connected in any way. Your live account is not known to the sandbox and vice versa.



Do not try to use the sandbox for live billing!

Sandbox accounts can be used as a staging system. The sandbox looks and behaves exactly as the live application but receives updates a little earlier and doesn't have the same level of redundancy and availability. The sandbox doesn't support live billing.