This document summarizes the scope and general principles of coordination under EU Regulations 883/2004 and 987/2009. It discusses the personal scope, which broadly includes EU citizens and their family members who are subject to social security legislation in one or more EU countries. It also examines the material scope, which primarily covers social security benefits but excludes social assistance. Key coordination principles are then outlined, including determining applicable legislation, equal treatment, assimilation of facts, aggregation of periods, export of benefits, and administrative cooperation between member state institutions.