This contribution presents a publication tool for digital edition, EVT – Edition Visualization Tachnology, developed by the University of Pisa. Born as a visualizer for a diplomatic edition to be visualized with the reproduction of the manuscript, the Digital Vercelli Book, EVT has subsequently evolved in a powerful and flexible software, which is able to publish digital critical editions as well. In the last part some comments about the latest specifications are proposed, such as the visualisation of the collating of a manuscript, the integration between diplomatic and critical editions, and the future perspectives of the project. In addition, briefly describing the technical specifications of EVT, the article focuses on the issues of modelling a text and the XML/TEI coding, that is the standard for digital critical editions. Then it presents the way in which the different parts of a critical edition are processed and visualized by the software.