<p>CATMA (Computer Aided Textual Markup and Analysis) is a free, open source markup and analysis tool from the University of Hamburg's Department of Languages, Literature and Media. It incorporates three interactive modules, a tagger enabling textual markup and markup editing, an analyzer incorporating a query language and predefined functions, and a query builder that allows users to construct queries from combinations of pre-defined questions while allowing for manual modification for more specific questions. It also interfaces with the Voyant toolset. As of version 4.1, CATMA is a web application with collaborative work functions, and improvements to its user interface, queries and corpus analysis capacity.</p>