SOAP
SOAP (Simple Object Access Protocol) is a protocol specification for exchanging structured information in web services using XML. It defines a messaging framework that allows programs running on disparate operating systems to communicate via HTTP and other protocols. SOAP web services are known for their strict standards, built-in error handling, and support for complex operations.
Developers should learn SOAP when building enterprise-level applications that require high reliability, security, and transactional support, such as in banking, healthcare, or government systems. It is particularly useful in scenarios where interoperability between different platforms (like .NET and Java) is critical, and when services need to follow strict contracts defined by WSDL (Web Services Description Language).