Regulation № 883/04, and the regulation on its application № 987/09require data to be exchanged electronically between institutions. This will be done through the EESSI system. Structured Electronic Documents (SED) have been designed to make communication of data between institutions easier and more efficient.

During the transitional period between 1 May 2010 and the entry into production of the EESSI system, paper versions of the SEDs can be used.