Open Zaak is based on the reference implementation of the “API’s voor Zaakgericht werken” made by VNG Realisatie. The overall architecture remains faithful to the Common Ground principles and all API specifications.

The architecture of Open Zaak focusses on excellent performance, optimal stability and to guarantee data integrity.

To that end, Open Zaak combines the “API’s voor Zaakgericht werken” that are essentially tightly coupled, into a single product. This allows for major performance improvements since related objects (like a BESLUIT for a ZAAK) do not need to fetched over the network but can be directly obtained from the database. This also guarantees data integrity on database level, rather than on service (API) level.

In addition, Open Zaak uses caching wherever possible to prevent needless requests over the netwerk to fetch data from external API’s. Data integrity can not be guaranteed on database level when relations are created to external API’s. In this case, data integrity is enforced on service level as much as possible.

The use of external API’s is fully supported in Open Zaak, even for API’s that are also offered by Open Zaak itself. For example, a ZAAK in Open Zaak, available via the Zaken API can have a DOCUMENT that is accessible via an external Documenten API from another vendor. The only requirement is that all API’s adhere to VNG standards for “API’s voor Zaakgericht werken”.

No permanent copies are made of original sources in Open Zaak as dictated by the Common Ground principles.


Architectural overview of component inside and related to Open Zaak.