The First Federal Congress Projec (FFC) is one of the first XML mini-editions published by the Model Editions Partnership. Generally speaking, XML (Extensible Markup Language) is a subset of SGML (Standard Generalized Markup Language). Both XML and SGML allow users to add intelligence to the text in a way that is difficult or impossible to accomplish in HTML.

The markup in the XML editions are based on the Partnership's SGML DTDs (Document Type Definitions) which were revised to conform to the XML protocols. Much of the MEP system is based on the DTDs developed by the Text Encoding Initiative (TEI). More than thirty seasoned documentary editors participated in modifying and extending the TEI system in the 1990s. Like most markup systems, MEP's system is modified from time to time as new forms of text are encountered.