The next step after documenting the web service interfaces is service discovery, which allows applications to find and connect to the services implemented by other parties.
Universal Description, Discovery, and Integration (UDDI) is a registry for WSDL files that may be searched manually or automatically. As with the other technologies discussed in this section, UDDI uses an XML format.
UDDI registry may be queried with SOAP messages for automated service discovery. Even though UDDI provided the logical extensions of WSDL, its adoption in the open was disappointing. It is still possible to find UDDI systems used internally by companies.