DeX is an easy to use and powerful expert system for estimating the prospective market value of Internet domain names. It can handle any Top Level Domain, and is based upon advanced multi-steps algorithm, which uses several criteria to determine the domain quality. User interface is simple and fully functional, and allows for individual domains processing, as well as for batch processing of domain name lists. The Domain Expert system can be configured and enhanced on the fly, so as to satisfy the needs of various business fields, and to adequately respond to quickly changing domain market. Besides, quick access to domain auctions and registrars on the Web is provided for the users that wish to sell/register the domains just evaluated.