Government & open data
GEMMA & NORA
GEMMA is the Dutch municipal model architecture: the reference architecture for Dutch municipalities, developed and maintained by the architecture knowledge centre of VNG Realisatie together with municipalities, suppliers and chain partners. It describes how municipal processes, information systems, data and infrastructure hang together, and alongside the base architecture it holds thematic architectures such as Common Ground and case-oriented working, plus standards and information models. NORA is the broader Dutch government reference architecture, managed by ICTU; GEMMA belongs to the NORA family. Together they form the set of agreements within which government bodies design their digital services.
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What this source does not give you
Neither is legislation. GEMMA states itself that it does not prescribe exactly what municipalities must do and leaves room for choices within their own context. The NORA architecture agreements are binding, but on the basis of administrative decision-making rather than a statute: the cabinet set NORA as the norm for all of government in 2008, and the government-wide policy consultation on digital government reaffirmed the current version on 21 September 2023.
Frequently asked questions
- Is a municipality obliged to follow GEMMA?
- No. GEMMA is a reference architecture: municipalities use it to develop their own enterprise architecture, but it does not prescribe exactly what a municipality must do and leaves room for choices in their own context. What can be hard are the standards GEMMA points to, such as API standards and information models, and the statutory requirements that apply independently of GEMMA. The architecture itself is an aid, not a norm with legal force.
- What does it mean that NORA agreements are binding?
- It means that every government organisation implementing a change must check whether it adheres to the connecting architecture agreements. The working method is apply-and-explain, a tightening of comply-or-explain: you apply all the agreements unless there are good reasons to deviate, and you document both the application and the deviation, including when you will revisit the trade-off. In some cases private parties are bound too if they work on public service delivery, for instance hospitals, government suppliers and foundations with a public task.
- How can I see how binding a NORA page is?
- Every page in the NORA wiki carries metadata with a degree of obligation, with four possible values: informative, recommended, mandatory and legally mandatory. It also shows a management phase and a contact person. That matters when citing: many explanatory pages are themselves marked informative, even where they describe binding agreements.
- Why does an older document refer to NORA basic principles I can no longer find?
- Because they have lapsed. NORA's ten basic principles and the derived principles expired on 1 January 2023 with the renewed architecture agreements. They have been replaced by a structure of core values, quality objectives, architecture principles and implications, organised into four levels from abstract to concrete. Documents from 2022 or earlier may therefore refer to a principle that no longer exists.
- What if a NORA agreement clashes with my sector's requirements?
- That is anticipated. NORA acknowledges that the nature or environment of a service can impose unique requirements, and for healthcare it points to DIZRA, a separate set of architecture agreements that supplements NORA where needed; there are more such supplementary architectures in the NORA family. A temporary deviation is also possible, for instance with legacy systems for which no alternative yet exists, but then a roadmap or plan to comply later belongs with it. Law and regulation prevail in any case: the agreements help in meeting them, they do not replace them.