SOAP (abbreviation for Simple Object Access Protocol) is a messaging protocol specification for exchanging structured information in the implementation of web services in computer networks. Its purpose is to provide extensibility, neutrality, verbosity and independence. It uses XML Information Set for its message format, and relies on application layer protocols, most often Hypertext Transfer Protocol (HTTP), although some legacy systems communicate over Simple Mail Transfer Protocol (SMTP), for message negotiation and transmission.

SOAP allows developers to invoke processes running on disparate operating systems (such as Windows, macOS, and Linux) to authenticate, authorize, and communicate using Extensible Markup Language (XML). Since Web protocols like HTTP are installed and running on all operating systems, SOAP allows clients to invoke web services and receive responses independent of language and platforms.

SOAP provides the Messaging Protocol layer of a web services protocol stack for web services. It is an XML-based protocol consisting of three parts:

  • an envelope, which defines the message structure[1] and how to process it
  • a set of encoding rules for expressing instances of application-defined datatypes
  • a convention for representing procedure calls and responses

SOAP has three major characteristics:

  1. extensibility (security and WS-Addressing are among the extensions under development)
  2. neutrality (SOAP can operate over any protocol such as HTTP, SMTP, TCP, UDP)
  3. independence (SOAP allows for any programming model)

oGaTe and IIX Gateway (Insurance oGaTe) support SOAP API