SOAP

The server then returns a SOAP response (an XML-formatted document) with the resulting data, e.g., prices, location, features.

[citation needed] SOAP was designed as an object-access protocol and released as XML-RPC in June 1998 as part of Frontier 5.1 by Dave Winer, Don Box, Bob Atkinson, and Mohsen Al-Ghosein for Microsoft, where Atkinson and Al-Ghosein were working.

SOAP originally stood for "Simple Object Access Protocol" but version 1.2 of the standard dropped this acronym.

After SOAP was first introduced, it became the underlying layer of a more complex set of web services, based on WSDL, XSD and UDDI.

SOAP may also be used over HTTPS (which is the same protocol as HTTP at the application level, but uses an encrypted transport protocol underneath) with either simple or mutual authentication; this is the advocated WS-I method to provide web service security as stated in the WS-I Basic Profile 1.1.

SOAP also has an advantage over DCOM that it is unaffected by security rights configured on the machines that require knowledge of both transmitting and receiving nodes.

XML Information Set was chosen as the standard message format because of its widespread use by major corporations and open source development efforts.

While it facilitates error detection and avoids interoperability problems such as byte-order (endianness), it can slow processing speed and can be cumbersome.