WSDL2Apex

In plain words: SOAP API integration in Salesforce Apex enables your org to exchange structured, XML-based messages with external enterprise systems. By importing a WSDL document into Salesforce using the built-in WSDL2Apex wizard, the platform auto-generates strongly typed Apex classes that use WebServiceCallout.invoke to send requests and parse responses with minimal manual parsing. While lightweight REST integrations with JSON payloads dominate modern web APIs, many mission-critical enterprise systems—including legacy ERPs, banking networks, and government data exchanges—rely strictly on the SOAP (Simple Object Access Protocol) standard. Salesforce Apex provides native support for both consuming external SOAP services via WSDL2Apex callouts and exposing custom Apex methods as SOAP web services.