What is the difference between a client and a customer in real estate?

A client is the party with whom the agent has a formal agency relationship and to whom the agent owes full fiduciary duties. A customer is the other party in the transaction whom the agent treats fairly and honestly but does not represent. For example, when a listing agent shows a property to an unrepresented buyer, the seller is the client and the buyer is the customer. The agent must treat the customer fairly, disclose material defects, and not misrepresent facts, but the agent does not owe the customer loyalty, confidentiality, or obedience to their instructions.