XML databases

data persistence software system that allows data to be specified, and sometimes stored, in XML format

BaseX is a native and light-weight XML database management system and XQuery processor, developed as a community project on GitHub. It is specialized in storing, querying, and visualizing large XML documents and collections. BaseX is platform-independent and distributed under the BSD-3-Clause license.

eXist-db (or eXist for short) is an open source software project for NoSQL databases built on XML technology. It is classified as both a NoSQL document-oriented database system and a native XML database (and it provides support for XML, JSON, HTML and Binary documents). Unlike most relational database management systems (RDBMS) and NoSQL databases, eXist-db provides XQuery and XSLT as its query and application programming languages.