Sav ZAPI is a Java(tm) API forming new powerful "Java/Zigzag" language, for development of the high-performance mobile object-relational database applications. Sav ZAPI provides synchronous connection many of users with many of databases. The main advantage of Zigzag over SQL is manipulation with classes, not just relations. Zigzag (or Z) algebraic expressions enable to process XML data with dynamic structure and multi-level hierarchy. Unlike XSLT, Zigzag is not data filter; it reads many of XML files in one database and then generates and prints new XML files.