Data spaces play a pivotal role in advancing digitalisation and interoperability within and across different business domains, both on a national level and cross-borders. However, it’s not a new concept since its roots date back to 2005. The definition has evolved over the years and today it covers all four layers of interoperability defined by the European Interoperability Framework (EIF). Today, the term data space has several different definitions depending on whom you ask. Also, multiple international initiatives are working on data spaces to create common governance models, specifications, reference implementations, etc. The aim of this talk is to discuss the data space concept, different actors working on data spaces and their roles and responsibilities, and available specifications and building blocks. This talk provides a basic understanding of what are data spaces and how they affect existing data ecosystems and APIs.