The Once-Only Principle Project (TOOP) was a project launched by the European Commission between January 2017 and March 2021. It was an initiative of about 50 organisations from 17 EU Member States and Associated Countries.

TOOP Project was funded by the European Union’s Horizon 2020 research and innovation programme under grant agreement No 737460.

The main objective of TOOP was to explore and demonstrate the Once-Only Principle across borders, focusing on data from businesses. Doing this, TOOP wanted to enable better exchange of business related data or documents with and between public administrations and reduce administrative burden for both businesses and public administrations.

The TOOP project consortium comprised around 50 organisations from 17 EU Member States and two Associated Countries.

Coordinator: Tallinn University of Technology (Estonia).

Countries: Austria, Bulgaria, Denmark, Estonia, Finland, France, Germany, Greece, Italy, Latvia, Luxembourg, Netherlands, Norway, Poland, Romania, Sweden, Slovenia, Slovakia, Switzerland.

Sectors: Public administration organisations, research organisations, private companies.

More information is available on the TOOP website.