Open data portals facilitate access to and re-use of public sector information.

Open data portals are web-based interfaces designed to make it easier to find re-usable information. Like library catalogues, they contain metadata records of datasets published for re-use, i.e. mostly relating to information in the form of raw, numerical data and not to textual documents. In combination with specific search functionalities, they facilitate finding datasets of interest. Application Programming Interfaces (APIs) are also often available, offering direct and automated access to data for software applications.

Open data portals are an important element of most open data initiatives and are mainly used by public administrations at European, national and local level in the Member States. Notable examples of Open Data portals maintained by public administrations in Europe are:

While supporting the policy by offering easy access to data published, they can also work as a catalyst triggering the publication of more and better quality data. For administrations obliged or willing to disseminate their data, they offer the advantage of providing public access without the need to reply to individual requests for access to data. Also, more and more companies are opening up some of their data for developers to re-use.

The European Commission offers an open data portal for any type of information held by the Commission and other EU institutions and bodies.This European Union's Open Data Portal is in operation since December 2012.

The European Data Portal

Since 2015, the European Commission has funded the European Data Portal through the Connecting Europe Facility programme. This is a pan-European repository of public sector information open for reuse in the EU. This portal also offers a training centre on how to reuse open data and a database of success stories from European and international re-users.

The principal function of the European Data Portal is to provide a single point of access in all 24 EU official languages for data published by public administrations at all levels of government in Europe (EU countries, countries of the European Economic Area and certain other European countries). In order to foster comparability of data published across borders, it represents metadata references in a common format (Data Catalog Vocabulary application profile for data portals in Europe) using Resource Description Framework (RDF) technology. Using machine-translation technology, it provides translations of metadata descriptions in all 24 languages.

The portal complements national, regional or thematic Open Data portals, as well as the European Union's Open Data Portal. Each of them target relevant user audience, offering tailored content. This infrastructure will stimulate cross-border use of re-usable information in Europe by improving the findability of data across countries and supporting the development of data applications and products including data from different countries, for example, by offering assistance on applicable licensing conditions.