The WSDL standard by W3C defines a web service description in XML. For each service, the description specifies all the data types and message formats used by the service, the message encoding and the communication protocol supported by the service, and the network addresses of the service. The description thus provides all the information that is required to set up communication with the service.

<?xml version="1.0"?>
<definitions name="StockQuote"
             targetNamespace="http://example.com/stockquote.wsdl"
             xmlns:tns="http://example.com/stockquote.wsdl"
             xmlns:xsd="http://example.com/stockquote.xsd"
             xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"
             xmlns="http://schemas.xmlsoap.org/wsdl/">

  <!-- Types used in communication -->
  <types>
    <schema targetNamespace="http://example.com/stockquote.xsd"
            xmlns="http://www.w3.org/2000/10/XMLSchema">
      <element name="TradePriceRequest">
        <complexType>
          <all>
            <element name="tickerSymbol" type="string"/>
          </all>
        </complexType>
      </element>
      <element name="TradePriceReply">
         <complexType>
           <all>
             <element name="price" type="float"/>
           </all>
         </complexType>
      </element>
    </schema>
  </types>

  <!-- Messages exchanged in communication -->
  <message name="GetLastTradePriceInput">
    <part name="body" element="xsd:TradePriceRequest"/>
  </message>
  <message name="GetLastTradePriceOutput">
    <part name="body" element="xsd:TradePriceReply"/>
  </message>

  <!-- Ports available in communication -->
  <portType name="StockQuotePortType">
    <operation name="GetLastTradePrice">
      <input message="tns:GetLastTradePriceInput"/>
      <output message="tns:GetLastTradePriceOutput"/>
    </operation>
  </portType>

  <!-- Bindings used in communication -->
  <binding name="StockQuoteSoapBinding" type="tns:StockQuotePortType">
    <soap:binding
      style="document"
      transport="http://schemas.xmlsoap.org/soap/http"/>
    <operation name="GetLastTradePrice">
      <soap:operation soapAction="http://example.com/GetLastTradePrice"/>
      <input><soap:body use="literal"/></input>
      <output><soap:body use="literal"/></output>
    </operation>
  </binding>

  <!-- Service -->
  <service name="StockQuoteService">
    <documentation>Stock quoter service.</documentation>
    <port name="StockQuotePort" binding="tns:StockQuoteSoapBinding">
      <soap:address location="http://example.com/stockquote"/>
    </port>
  </service>

</definitions>

<!-- Example adjusted from WSDL 1.1 Specification. -->