Sav Z API is a Java(tm) API forming new powerful "Java/Z" language, for development of a high-performance mobile object-relational database application. Like SQL JDBC implementation, Sav Z API provides synchronous connection many of users with many of Z databases. Main advantage of Z to SQL is manipulation with classes (not only relations). Z algebraic expressions enable to process XML data with dynamic structure and multi-level hierarchy. Unlike XSLT, Z is not data filter; it reads many of XML files in one database and than generates and prints new XML files.