Data portals are (usually) publicly accessible websites on which an organization's data is made available in a structured format comprehensible to laypeople. These organizations can be cities, municipalities, NGOs, or political organizations such as governments or government departments/ministries. As soon as the data in the data portals are publicly accessible, they are "open data" portals. Data portals can contain a wide variety of data types - from texts to tables, images and data visualizations (including interactive visualizations), as well as videos and 3D models.
Increasingly, data portals are also used as a place for municipal stakeholders to exchange data without making all of their content publicly available. In addition, data portals can be used as a central directory service ("Active Directory") for open urban data platforms.