OPSI is established on the basis of the EU Directive on the re-use of public sector information and legislation on access to public information (ZDIJZ), constitutes a single national website section for publishing open data for the whole public sector.

OPSI has a dual function:

1) provides a central catalog records and databases in the country, ie central inventory of metadata about all the records and databases kept by state authorities, municipalities and other public sector bodies;

2) represents a single site for the publication of data from databases in open and machine-readable formats. As far as certain collections in open formats have already been published on another website, the portal OPSI website link listed on this site.

Portal OPSI addition to the data of state bodies including the publication of open data community. The portal provides everyone the right to a free and easy to re-use those freely available data published by means of 'open data' ie for any (non-profit / profit) purpose.

Open data published on the portal, the "open license" (the only condition of re-use is an indication of the source; CC BY 4.0 ).