RDAP is a HTTP-based protocol that delivers data in a standard, machine-readable JSON format. WHOIS is a text-based protocol and, as it doesn't have standardized queries and responses, the interaction with Registries can vary significantly. While Registry lookup and search services have traditionally been offered through WHOIS, it has a number of shortcomings, including the lack of a standard data model, the lack of support for internationalization and the inability to authenticate users to provide differentiated services to such classes of users.