SOAP - Why SOAP is Used

SOAP (Simple Object Access Protocol) is a messaging protocol that allows applications to exchange structured information over a network.

It is XML-based → all requests and responses are formatted in XML.
It is platform- and language-independent → a C# client can call a Java or PHP SOAP service.
It uses WSDL (Web Services Description Language) to describe available operations and data formats.

SOAP is used because it provides:

Standardized Communication – Systems written in different languages and running on different platforms can talk to each other.
Strict Contracts – The WSDL ensures both client and server know exactly what data types and operations to expect.
Transport Flexibility – Works not only over HTTP but also over SMTP, TCP, JMS, etc.
Security – Supports WS-Security (signatures, encryption, authentication).
Reliability – Built-in support for error handling (via Fault) and transactional operations.
Enterprise Adoption – Many large organizations use SOAP for mission-critical services because of its robustness and formality.

SOAP is used when you need reliable, secure, and standardized communication between applications, often in enterprise systems.