How do I check that the agent or broker is legitimate from overseas?

Insist on a RERA-registered broker and check their BRN (Broker Registration Number) card. Every legitimate listing carries a Trakheesi permit number you can validate. Cross-check the agent and firm on the DLD's Dubai REST app or the 'Dubai Brokers' service. Dealing with an unlicensed 'agent' is the single biggest risk for remote buyers.