What is SAX?

SAX is a serial access parser API for XML. Sax provides a mechanism for reading data from an XML document. It is a popular alternative to the Document Object Model (DOM). The name is acronymically derived from "Simple API for XML".

A parser which implements SAX (ie, a SAX Parser) handles XML information as a single stream of data. This data stream is unidirectional, such that previously accessed data cannot be re-read without reparsing.

Most users of XML believe that the SAX paradigm results in systematically faster XML processing than DOM. This is attributed to the fact that a SAX stream has a minuscule memory footprint compared to that of a fully constructed DOM tree.

The SAX parser is implemented as an event-driven model in which the programmer provides callback methods which are invoked by the parser as part of its traversal of the XML document.

SAX was developed collaboratively on the xml-dev mailing list, with no formal committee structure, but was quickly implemented by major companies working with XML. The original lead developer and maintainer was David Megginson.

About this Terminology
This terminology is from The Wikipedia which is published under the GNU Free Documentation License.