SOAP (Simple Object Access Protocol) is a protocol for exchanging structured information in the implementation of web services. It is a messaging protocol that allows programs running on different operating systems (such as Windows and Unix) to communicate over the Internet.
SOAP is based on XML (eXtensible Markup Language) and consists of three main parts: an envelope, which defines the structure of the message; a set of encoding rules for expressing instances of application-defined datatypes; and a convention for representing remote procedure calls and responses.
SOAP messages are typically sent over HTTP (Hypertext Transfer Protocol) or its secure variant, HTTPS, making it suitable for communication over the Internet. SOAP is language-agnostic, meaning that it can be used with programming languages such as Java, C#, and Python.
Example (SOAP Message): A simple example of a SOAP message:
<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
<SOAP-ENV:Header/>
<SOAP-ENV:Body>
<m:GetStockPrice xmlns:m="http://example.com/stock">
<m:StockName>IBM</m:StockName>
</m:GetStockPrice>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>