In this paper, we describe a high-level blackboard architecture for electronic commerce. The architecture relies on the presence of supply, demand, and broker agents. The blackboard includes a user agent to interface with the user to determine criteria and needs for particular services. In addition, we describe an evaluation agent that uses a knowledge based system to determine the acceptance, rejection, or negotiation status of services returned to the blackboard by demand agents. We illustrate the possible computation needed within the blackboard using a hotel service request example.