This paper describes the MARCXML architecture implemented at the Library of Congress. It gives an overview of the component pieces of the architecture, including the MARCXML schema and the MARCXML toolkit, while giving a brief tutorial on their use. Several different applications of the architecture and tools are discussed to illustrate the features of the toolkit being developed thus far. Nearly any metadata format can take advantage of the features of the toolkit, and the process of the toolkit enabling a new format is discussed. Finally, this paper intends to foster new ideas with regards t