Moving from ZDS to ZGW under Common Ground: should you replace your case system or your task applications first?

The Common Ground agreement, developed by the Association of Dutch Municipalities (VNG), was created in response to the need for a modern information architecture that makes data exchange simpler and more flexible.

To comply with Common Ground, municipalities must take a critical look at their IT infrastructure. Most existing case management systems and task applications are currently designed in a way that does not meet the new guidelines.

In this blog, we explain how to determine the best place to start when transitioning to case-oriented working in line with Common Ground.

Zaak and Document Services (ZDS) and Zaakgericht Werken (ZGW)

Until recently, and still today in many municipalities, task applications and case management systems were built around Zaak and Document Services (ZDS) APIs based on SOAP. This means that information was exchanged in large, aggregated messages between systems.

Under the Common Ground principles, new task applications and case management systems must use APIs for Zaakgericht Werken (ZGW), which are based on REST. With REST APIs, data is exchanged in smaller, discrete pieces.

It is easy to see that systems built on SOAP cannot communicate directly with systems built on REST. This makes the transition from the old situation to the new one a complex challenge.

Because of this complexity, it is strongly recommended to involve an integration partner who can support you throughout the process. If you are planning to outsource this trajectory, it is important to be aware of common pitfalls.

Replacing your case management system and task applications at the same time

One option is to replace your entire IT landscape in one go, ensuring that all systems immediately communicate correctly with one another. In practice, however, this is not a realistic approach for a municipality. Municipal operations cannot afford downtime, and there are many moving parts to consider, including dependencies and contracts. Planning a complete switch all at once is therefore extremely difficult.

Another option is to create a hybrid transition model, in which the case management system, either fully or partially, is replaced at the same time as a number of task applications. This strategy is often used in practice, but it does require a high level of integration expertise to ensure everything runs smoothly.

Should you start with the case management system or with the task applications?

If you replace the case management system first, your task applications will temporarily be unable to communicate with it. The new case management system will use REST APIs, while the task applications will still rely on SOAP.

With this approach, task applications are replaced step by step after the new case management system is in place. During the transition, municipal employees will need to work separately in the task applications and in the case management system.

If you choose to start with the task applications, the communication challenge is reversed. The task applications will be based on REST APIs, while the case management system will still operate on SOAP. In this scenario, it is often more convenient for municipal employees to work primarily from the task applications. When the case management system is eventually replaced, all updated task applications can be connected to complete the transition.

Whether it is better to start with the case management system or with the task applications depends entirely on how your municipality operates and which approach best fits your processes. Unfortunately, there is no one-size-fits-all solution.

What works best for your municipality?

Are you unsure whether your municipality should start by replacing task applications or the case management system? We have created a checklist that helps you determine the most suitable route for your situation. Download the checklist here.