The position paper underlines the importance of data spaces and though the sovereign sharing of data in creating the future data economy. It has been developed under the coordination and leadership of Task Force 1 lead by International Data Spaces Association of the Horizon 2020 project “OPEN DEI Aligning Reference Architectures, Open Platforms and Large-Scale Pilots in Digitising European Industry” with the collaboration of more than 40 data spaces and industrial domain experts representing more than 25 organisations from 13 Horizon 2020 projects and related initiatives. This is the first approach to define the design principles for data spaces, agreements on the building blocks for a soft infrastructure and governance for data spaces.