The registered exporter system (REX) is the origin certification system that the European Union applies in its preferential trade arrangements: the Generalised Scheme of Preferences (GSP) and several free trade agreements, including those with Canada, Japan, Vietnam and the United Kingdom.
The REX system is based on self-certification by economic operators, who issue the so-called statements on origin themselves. To be allowed to make a statement on origin, an economic operator must ask its competent authorities to be registered in a dedicated database. It then becomes a registered exporter.