APEX_WEB_SERVICE package enables you to integrate other systems with Oracle Application Express by allowing you to interact with Web services anywhere you can use PL/SQL in your application. The API contains procedures and functions to call both SOAP and RESTful style Web services.
It contains functions to parse the responses from Web services and to encode/decode in to SOAP friendly base64 encoding.This API also contains package globals for managing cookies and HTTP headers when calling Web services whether from the API or by using standard processes of type Web service. Cookies and HTTP headers can be set before invoking a call to a Web service by populating the globals and the cookies and HTTP headers returned from the Web service response can be read from other globals.
All Web services must be secured. Only HTTPS services are supported. Simple HTTP requests will be rejected. The proxy server that is usually configurable is preset as an Oracle provided HTTP proxy server and not changeable by users.
To learn more, see APEX_WEB_SERVICE in Oracle Application Express API Reference.