The legal frame
Article 22 of the Vienna Convention establishes mission inviolability and the receiving state's special duty of protection. Most host states meet this with police presence and bilateral protocols; the embassy itself remains responsible for internal security, access control, screening, and coordination with the host police.
For consulates, the Vienna Convention on Consular Relations (1963) establishes a comparable but slightly narrower frame. The practical security implications are similar: the host state provides external coverage; internal security is the mission's responsibility.
What the sending state expects
Sending states typically require: cleared personnel for sensitive positions, documented operational procedures, secure communication where required, regular threat assessment, and incident-reporting compliance. Many ministries publish vendor-vetting standards that suppliers must meet.
These standards rarely match the receiving state's licensing one-to-one. A serious supplier holds both — and can show, in writing, how its personnel are vetted and how its operations comply with each side's requirements.
What the receiving state expects
Most member states require all on-site officers to hold the national security licence (Wpbr in the Netherlands; equivalent regimes elsewhere). Armed positions require additional permits. Officers without proper licensing on a diplomatic site are a procurement and reputational risk to the mission.
Permitted activities — access control, screening, patrol, escort — are also defined by national law. A supplier should know exactly what its officers can and cannot do under the receiving state's regime.
How to evaluate a supplier
Beyond licensing, ask: what is your operational doctrine for diplomatic sites; how are officers vetted; how do you coordinate with the host police service; how do you handle a positive find at screening; how do you escalate a security incident to the head of mission; and how do you document the engagement to a standard that survives a host-state inspection or a sending-state audit?
These questions exclude most generalist firms. They are exactly the questions a serious supplier expects to answer.