Apache Software Foundation's Apache Xindice 1.0 and Sleepycat Software's Sleepycat Berkeley DB XML 2.0 are reviewed eXtensible Markup Language (XML) databases that can form content management foundations. They are database libraries that form the basis for larger content management applications. Both products are open source and both are free, although in different ways. Both provide standards-compliant XML document manipulation and are robust developer tools that give programmers attention-getting XML document storage, query, and retrieval abilities. Xindice 1.0 is free with an Apache license, and Sleepycat is free with a Sleepycat License, with some restrictions based on application use and distribution. Xindice has a client/server architecture, and Sleepycat Berkeley DB XML 2.0 has a Link-in library. Sleepycat can support large documents and uses a command-line interface with multiple language bindings. Apache Xindice 1.0 has a command-line and the DB XML application programming interface (API). Xindice 1.0 gets its highest marks for interoperability, scalability, setup, and value, while Sleepycat Berkeley DB XML 2.0 is rated highest for interoperability and value, which are excellent. Xindice is highly approachable for Java programmers, and Berkeley DB XML is a super XML database library that runs a layer above the highly secure Berkeley DB. Sleepycat has added XQuery support not found in Xindice 1.0, and new documentation eases learning. eXist 1.0 from the eXist Project is described as a worthwhile study in the power of XQuery, with excellent tutorials and documentation. Its an open source gem.