The Registered Exporter system (the REX system) is the system of certification of origin of goods that applies in the Generalised System of Preference (GSP) of the European Union since January, 2017. It is based on a principle of self-certification by economic operators who will make out themselves so-called statements on origin. To be entitled to make out a statement on origin, an economic operator will have to be registered in a database by his competent authorities. The economic operator will become a "registered exporter".
The REX system was introduced in the GSP rules of origin by the amending Regulation (EU) No 1063/2010 in the context of the reform of the GSP rules of origin in 2010. While the other elements of the reform have taken their effect as from January 2011, the application of the REX system has been deferred to January 2017, to give enough time to the GSP beneficiary countries to be ready.
The REX system will progressively and completely replace the current system of origin certification based on certificates of origin issued by governmental authorities and on invoice declarations made out under certain conditions by economic operators. This means as well that the REX system is used between GSP beneficiary countries applying regional cumulation.
The global transition period from the current system of origin certification to the REX system started on January 01, 2017 and will last until June 30, 2020 at the latest.
More information about the REX system
You will find more information in the whole article concerning the transition period and here you also will find an updated list of Countries added to the REX regulation.
Source: European Commission