SOAP
SOAP (Simple Object Access Protocol) is a standardised, XML-based protocol for exchanging structured information between systems as web services. Older and more rigorous than REST, SOAP defines a strict message envelope and a formal contract (a WSDL) describing the available operations, and includes built-in standards for security, transactions and reliability (the “WS-*” specifications).
SOAP was the dominant web-service style before REST, and remains in use in enterprise, financial, government and legacy integrations where its formal contracts and built-in security features are valued — including some carrier, customs and banking interfaces in the logistics and trade world. Its trade-offs are that it is heavier, more complex and more verbose than REST/JSON, which is why most new logistics APIs are RESTful. When integrating systems, teams still frequently encounter SOAP services alongside modern REST APIs, so understanding it is useful for connecting to established partners and legacy platforms. SOAP is part of the mixed landscape of interfaces that logistics and ERP integration must accommodate.
SOAP predates REST and lingers wherever formal contracts and built-in security matter — enterprise, banking, customs and carrier interfaces. Integrations still routinely meet SOAP services alongside modern REST APIs, so understanding it is practical necessity for connecting to established partners and legacy systems in trade and logistics.
How is SOAP different from REST?
SOAP is a formal XML-based protocol with strict contracts (WSDL) and built-in security; REST is a lighter, flexible style using standard HTTP and usually JSON.
Why is SOAP still used?
Its formal contracts and built-in security suit enterprise, government, banking and legacy interfaces, some of which appear in logistics and customs integration.