About usWe collaborate to build a dataspace and the future of the Single Market
The European Commission and EU Member States are committed to simplifying cross-border online procedures by allowing citizens and businesses to supply the same data to public authorities ‘only once’.
![illustration Once Only Technical System shows a building with stars](https://ec.europa.eu/digital-building-blocks/sites/download/attachments/592642684/illu-about-us-introduction.png)
Our mission
The Once-Only Technical System makes administrative processes easy for people and businesses.
Authentication to any online procedure portal in Europe using a national eID
Identification of equivalent documents in any Member State
Easy request for sharing documents or data between the authorities
Interoperability with the building blocks
The Once-Only Technical System will create an interoperability layer based on common and mature building blocks funded under the Digital Europe Programme. It will use the eIDAS cross-border electronic identification building block, known as eID. In addition, the eDelivery access points will create a virtual secure network on top of the public internet. The OOTS will also be fully compatible with the future European Digital Identity Wallet as a new means of authentication to public services offering the ‘once-only’ option.
![illustration Once Only Technical System (OOTS), a laptop shows Interoperability with the building blocks](https://ec.europa.eu/digital-building-blocks/sites/download/attachments/592642684/illu-about-us-interoperability.png)