SOAP (Simple Object Access Protocol) API is a protocol designed to exchange structured information in web services. Unlike REST APIs, which rely on a stateless, resource-based approach, SOAP is a highly standardized protocol that relies on XML for message formatting and is designed to enable communication between applications over the internet or other networks.
SOAP uses XML (Extensible Markup Language) to encode messages. XML ensures that data can be read by different systems regardless of the platform or programming language they use, making SOAP APIs highly interoperable.
While HTTP and HTTPS are commonly used, SOAP is protocol-agnostic, meaning it can operate over SMTP (email), TCP, and other network protocols.
SOAP APIs adhere to strict standards defined by the World Wide Web Consortium (W3C) and support extensive security protocols like WS-Security, ensuring data integrity and confidentiality. SOAP services are described by a WSDL document. This XML-based document provides detailed information about the service, including available operations, request and response formats, and endpoints, making it easy to understand and use the SOAP API.
Use Cases for SOAP API
- Enterprise Applications: Many legacy systems and enterprise applications, such as ERP and CRM software, still use SOAP APIs for secure data exchanges.
- Financial Services: With its high security and reliability standards, SOAP is often used in financial services where data integrity and confidentiality are paramount.
- Healthcare: SOAP APIs are frequently used in healthcare, where secure, reliable messaging is critical for handling sensitive data.