fast XML database engine fully supporting XQuery. Qizx is designed to perform high-speed querying, retrieval and processing of indexed XML contents. Works with well-formed XML documents. Does not require DTD or Schema. By default, the full contents of documents are indexed: elements, attribute values (in text/numeric/date forms when applicable), simple element content, full-text. Consequence: out of the box, queries execute at best speed. For advanced needs, the indexing process in an XML Library can be configured through context-sensitive rules for elements and attributes, and/or pluggable value converters and full-text word tokenizers. A repository (named a XML Library) is organized as a hierarchical structure of Collections, which in turn contain Documents (similar to a file-system, with collections playing the role of directories and XML documents the role of plain files). Indexed Documents and Collections can be decorated with queriable metadata properties. To support XQuery, XML documents indexed in Qizx have an internal representation that complies with the XQuery/XPath 2 Data-Model: their logical structure is fully preserved and documents can be exported back into XML without loss of information (except for physical details like entity boundaries and CDATA sections). Documents and indexes are compressed, which allows a significant reduction of disk space use and IO: an XML Library with all its indexes (including full-text) is often slightly smaller than the source XML. Qizx does not currently support the storage of non-XML data, such as images. However metadata properties associated with Documents, Collections or Libraries make it easy to keep links with data stored on other media.