- Published: 06.03.2026.
Implementation of ‘Once-Only’ principle: Improvement of e-government procedures in Croatia
As part of the systematic digitalisation of the public administration, Croatia has successfully introduced the Once-Only Technical System (OOTS), which has brought the ‘Once-Only’ services to life in practice
The efforts and achievements of Croatia in the implementation of these solutions have been recognised by the European Commission.
Croatia thus confirmed its commitment to modernisation, enabling Croatian citizens and citizens of other EU member states to carry out cross-border procedures, when moving to or doing business in another EU country, in a faster and simpler way through the e-Citizens portal. Currently, 19 out of the 21 SDG procedures covered by the Single Digital Gateway Regulation have been successfully integrated into the system.
Functionalities of the Once-Only Technical System (OOTS)
The system is based on the European ‘Once-Only’ principle, an e-government concept where citizens and businesses are not obliged to provide the same data or documents to different public authorities repeatedly.
The OOTS allows documents such as diplomas, certificates or certificates to be automatically retrieved directly from the registers of the country of origin, with the prior consent of the user.
This approach significantly reduces the administrative burden by eliminating the need to manually upload digitally available documents, while ensuring a high level of security through the use of digital identity and advanced data protection protocols.
Most popular OOTS digital procedures
Through the e-Citizens portal, Croatia offers a wide range of e-services that cover the most important life and business situations.
Among the most popular digitalised procedures is the application for enrolment in a higher education institution, which includes the submission of the initial application and all supporting evidence in digital form.
Significant progress has also been made in the area of tax administration, where the authorities are now obliged to accept income tax returns in digital format, allowing users to settle their tax obligations without having to physically go to the competent institutions.
A special focus has been placed on facilitating business activities. Legal entities and self-employed persons already registered in other Member States can send notifications about business activities or e.g. posting of workers digitally.
Furthermore, the system supports professionals in the process of obtaining a licence to work in regulated professions and enables digital applications for specific sectoral licences, such as those for driving schools.
Contributing to the Single Market and competitiveness
The full implementation of these services is an important step towards creating a more integrated and efficient European Single Market.
By reducing bureaucratic barriers and introducing automated digital processes, Croatia provides an enabling environment for education, work and investment.
This has a direct impact on increasing global competitiveness of the domestic economy and improving the quality of services for all Union citizens.
Detailed information on all available e-services and their terms of use is available as part of the service catalogue on the e-Citizens platform.
Croatia thus confirmed its commitment to modernisation, enabling Croatian citizens and citizens of other EU member states to carry out cross-border procedures, when moving to or doing business in another EU country, in a faster and simpler way through the e-Citizens portal. Currently, 19 out of the 21 SDG procedures covered by the Single Digital Gateway Regulation have been successfully integrated into the system.
Functionalities of the Once-Only Technical System (OOTS)
The system is based on the European ‘Once-Only’ principle, an e-government concept where citizens and businesses are not obliged to provide the same data or documents to different public authorities repeatedly.
The OOTS allows documents such as diplomas, certificates or certificates to be automatically retrieved directly from the registers of the country of origin, with the prior consent of the user.
This approach significantly reduces the administrative burden by eliminating the need to manually upload digitally available documents, while ensuring a high level of security through the use of digital identity and advanced data protection protocols.
Most popular OOTS digital procedures
Through the e-Citizens portal, Croatia offers a wide range of e-services that cover the most important life and business situations.
Among the most popular digitalised procedures is the application for enrolment in a higher education institution, which includes the submission of the initial application and all supporting evidence in digital form.
Significant progress has also been made in the area of tax administration, where the authorities are now obliged to accept income tax returns in digital format, allowing users to settle their tax obligations without having to physically go to the competent institutions.
A special focus has been placed on facilitating business activities. Legal entities and self-employed persons already registered in other Member States can send notifications about business activities or e.g. posting of workers digitally.
Furthermore, the system supports professionals in the process of obtaining a licence to work in regulated professions and enables digital applications for specific sectoral licences, such as those for driving schools.
Contributing to the Single Market and competitiveness
The full implementation of these services is an important step towards creating a more integrated and efficient European Single Market.
By reducing bureaucratic barriers and introducing automated digital processes, Croatia provides an enabling environment for education, work and investment.
This has a direct impact on increasing global competitiveness of the domestic economy and improving the quality of services for all Union citizens.
Detailed information on all available e-services and their terms of use is available as part of the service catalogue on the e-Citizens platform.