Postman - How to Test a SOAP Service Using Postman

Use Case:

A QA engineer or developer needs to validate a legacy SOAP web service provided by an enterprise application. However, there is no UI available for direct interaction and using tools like SOAP UI feels heavy. They prefer a lightweight, quick alternative—Postman.

Solution Steps:

Step 1: Gather SOAP Endpoint and WSDL

Obtain the following from the service provider:

• SOAP endpoint URL
• WSDL (Web Services Description Language) URL or XML
• Sample SOAP Request XML (if available)

Step 2: Open Postman

Launch Postman and open a new tab for a new request.

Step 3: Configure Request

• Method: POST
• URL: Enter the SOAP endpoint (e.g., https://example.com/soap/Service) and not the wsdl url(except ?wsdl part)
• Headers:
  • Content-Type: text/xml;charset=UTF-8
  • SOAPAction: (Optional — required for some services. Use the action URL from WSDL.)

Step 4: Add the SOAP Envelope in the Body

• Switch to the Body tab
• Select raw
• Choose XML (text/xml) from the dropdown
• Paste your SOAP XML envelope. Example:

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:web="http://webservice.example.com/">
   <soapenv:Header/>
   <soapenv:Body>
      <web:getUser>
         <web:userId>12345</web:userId>
      </web:getUser>
   </soapenv:Body>
</soapenv:Envelope>

Step 5: Send Request

Click Send. You’ll receive a SOAP XML response in the same format.

Step 6: Validate the Response

• Check for the correct tags in the SOAP Body.
• Look for fault tags (<soap:Fault>) to debug errors.

If authentication is required (Basic Auth, WS-Security), configure it under the Authorization tab or add headers manually.

How to Select a SOAP Operation in Postman

Step 1: Understand the WSDL File

Open the WSDL URL in a browser or download the XML. Look for the <wsdl:operation> tags. Each one represents an operation you can call.

Example:

<wsdl:operation name="getUser">
  ...
</wsdl:operation>

Step 2: Identify SOAPAction (Optional but often required)

Under each operation, the WSDL may define a soapAction attribute:

<operation name="getUser">
  <soap:operation soapAction="http://example.com/getUser"/>
</operation>

You’ll use this value in the SOAPAction header in Postman.

Step 3: Copy the Request XML for the Operation

Often, the WSDL (or service documentation) includes a sample request for each operation. If not, you can generate one based on the operation’s input schema.

Example SOAP request for getUser:

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:web="http://example.com/webservice/">
   <soapenv:Header/>
   <soapenv:Body>
      <web:getUser>
         <web:userId>12345</web:userId>
      </web:getUser>
   </soapenv:Body>
</soapenv:Envelope>

Step 4: Paste in Postman Body

Paste the envelope into Postman's body (as described earlier), and update the SOAPAction header (if required) with the operation’s SOAPAction URL.