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What is Open Data?

Open Data refers to data that is freely available to everyone, without restrictions on its use or distribution. This means that everyone, from researchers to developers and curious citizens can access archival data. Dutch government bodies are required to provide open datasets, but private institutions, companies and other organisations can also provide them.

This website contains all available open datasets from the organisations participating in An open data set can contain an entire finding aid, such as the archive of a municipality over a certain period. But also more detailed descriptions with, for example, birth certificates, or a collection of photographs.


The open datasets are created based on the following principles:

Open Data…
  • Is as complete as possible, so contains all public data and information
  • Contains only source data where no aggregation has been applied
  • Is made available as soon as possible
  • Is freely accessible, i.e. free and anonymous
  • Is in a machine-readable format so that automated processing is possible
  • Is set-up according to open standards and
  • Has an open licence (no restriction under copyright law, database law, or confidentiality, etc.)


A licence is assigned to a dataset; a licence states how a dataset may be reused. In the Netherlands, Creative Commons licences are used.

All open datasets found on this website are, in principle, available to anyone and can be downloaded anonymously. All available datasets are publicly accessible and copyright-free. Re-use is possible, but may in some cases be on the condition of referencing the original creator.

Goals of Open data

Opening up archival data enables enrichment through exchange of data:

  • Data can be re-used on another platform
  • Data can be used for (historical) analysis and research purposes
  • Other…

Contents of open datasets

This website contains all open datasets from participants. These are mainly archive services that hold government archives, but also private archives and records from (historical) societies can be found on An open dataset can include, for example, an archive of a (former) municipality, but a map or a collection of photographs is also possible. There is a large variety of material types, from genealogical information to land registry data to postcards.

Formats of Open Data

There are international standards when it comes to the arrangement of open datasets. It concerns the layout, which tags may be used and what legal information is required. There are many kinds of sources, therefore there are several different standards to suit all of them. These are four open standards:

  • A2A for genealogical sources (like birth certificates, civil registry and notarial deeds)
  • EAD for Finding aids
  • Dublin Core for audio-visual sources (like maps, photographs, and films)
  • XML for all other material

Using standardised formats ensures uniformity. The setup of an open dataset is therefore the same for all finding aids regardless of (governmental) provenance.

You can download an open dataset by selecting a dataset and opening the details page, there you will find a download button. It is also possible to harvest the data. Would you like to know more about this option please go to “About Harvesting”.

Creation of an open dataset

On records are updated daily.
An automated process creating open data files is initiated when linking specific open data licenses to the records which can subsequently be found on and downloaded from this website.
EAD-files are created and made available for harvest on a daily basis, however: A2A, Dublin Core and XML datasets are generated once a week at the weekend.
Please keep in mind that an open dataset is always a snapshot of the data at that moment. The data could be modified a week, a month or a year later.