Skip to content
Postman API Testing Tips

How To Test Soap Web Service Using Postman

API Testing Blog

Understanding SOAP Web Services and Postman

SOAP (Simple Object Access Protocol) is a messaging protocol that is used to exchange data between applications over a network. It is commonly used for web services and is XML-based. Postman, on the other hand, is a powerful tool designed for testing and interacting with APIs.

This guide will focus on using Postman to test SOAP web services, providing a comprehensive step-by-step approach with practical examples.

Prerequisites

  • Postman Installation: Download and install Postman from https://www.postman.com/.
  • SOAP Web Service Endpoint: You’ll need the URL of the SOAP web service you want to test. This URL will typically point to a WSDL (Web Services Description Language) file.
  • Basic Understanding of SOAP: Having some knowledge of SOAP concepts like requests, responses, and XML will be helpful.

Step-by-Step Guide: How to Test SOAP Web Services with Postman

1. Accessing the WSDL

  • Open Postman: Launch the Postman application.
  • Create a New Request: Click on the “New” button and select “Request” or simply press “Ctrl+N.”
  • Paste the WSDL URL: In the “Request URL” field, paste the URL of the WSDL file. This is crucial for Postman to understand the structure of the SOAP service.

Example:

https://www.example.com/services/MyService.wsdl

2. Setting up the Request

  • Select the HTTP Method: Since SOAP uses the POST method for sending requests, choose “POST” in the dropdown menu.
  • Headers: Postman automatically fills in some common headers. Add the following header:
Content-Type: text/xml
  • Body: This is where you define the SOAP request message. Postman offers a “Raw” view and a “Body” view. Choose “Raw” and select “XML” as the content type.

3. Building the SOAP Request

  • XML Structure: The SOAP request needs to be structured in a specific way. Postman helps create the XML structure by providing hints and suggestions.
  • Root Element: The request should start with the <soapenv:Envelope> element.
  • Headers and Body: Add the SOAP header elements (if required) and the body elements that contain the actual data being sent.
  • Namespace: Specify the namespace for the SOAP envelope and other elements. The namespace helps identify the elements uniquely. Use xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" and xmlns:targetnamespace="http://www.yourdomain.com/myService". Replace http://www.yourdomain.com/myService with the actual namespace of your SOAP service.

Example (Basic SOAP Request):

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
   <soapenv:Body>
      <ns1:myOperation xmlns:ns1="http://www.yourdomain.com/myService">
         <ns1:parameter1>Value1</ns1:parameter1>
         <ns1:parameter2>Value2</ns1:parameter2>
      </ns1:myOperation>
   </soapenv:Body>
</soapenv:Envelope>
  • Replace Placeholders: Replace Value1, Value2, and myOperation with the actual values and the method name you want to invoke in your SOAP service. Use the WSDL to get the correct attribute names and values.

4. Sending the Request

  • Send: Once the SOAP request is built, click on the “Send” button to send the request to the SOAP web service.

5. Analyzing the Response

  • Response Body: Look at the response body in the “Body” tab. The response will be in XML format, providing the result of the invoked SOAP operation. The response may include data or status information.
  • Headers: The “Headers” tab displays various headers included in the response, providing information about the communication.
  • Status Code: Check the status code in the “Status” section. A 200 OK status code usually indicates successful communication.

6. Testing Different Scenarios

  • Validating Data: Test the SOAP service with different valid input data and verify that the response is as expected.
  • Error Handling: Test the service with invalid or unusual input data to see how it handles errors. The response should contain appropriate error messages.
  • Performance: You can test the performance of the service by running multiple requests and measuring the response times. Pay attention to the “Time” section in Postman.
  • Security: Use Postman’s security features to test the authorization and authentication mechanisms of the SOAP service.

7. Saving and Sharing Tests

  • Collections: Organize your SOAP web service tests for better management by creating collections. You can group related requests in a collection.
  • Sharing and Collaboration: Postman offers features for sharing collections and tests with your team or within an organization. This promotes collaboration and standardization during API testing.

Practical Example: Testing a Weather SOAP Service

Let’s test a hypothetical weather service that provides current weather information for a given location. Here’s a breakdown:

  • WSDL URL: https://www.weather.com/services/WeatherService.wsdl
  • SOAP Operation: getWeatherData
  • Parameters:
    • location: Specifies the city and country.
    • units: Specifies the units (e.g., Celsius/Fahrenheit).

1. Setting up the Request:

  • URL: https://www.weather.com/services/WeatherService.wsdl
  • Method: POST
  • Content-Type: text/xml

2. Building the SOAP Request:

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ns1="http://www.weather.com/services">
   <soapenv:Body>
      <ns1:getWeatherData>
         <ns1:location>London, UK</ns1:location>
         <ns1:units>celsius</ns1:units>
      </ns1:getWeatherData>
   </soapenv:Body>
</soapenv:Envelope>

3. Sending the Request:

  • Send the request and examine the response.

4. Analyzing the Response:

The response will be in XML format. It should include information like:

  • City
  • Current temperature
  • Conditions (e.g., Sunny, Cloudy)
  • Humidity

By modifying the location and units parameters, you can test the service with different cities and units. This example illustrates how Postman can be used to test various aspects of a SOAP web service, from basic functionality to security and performance.

Conclusion: Mastering SOAP Web Service Testing with Postman

Postman is a powerful and versatile tool for testing SOAP web services. The step-by-step guide and practical example provided here demonstrate the key concepts and best practices for effectively using Postman to validate SOAP service functionality. By understanding the basics of SOAP and leveraging Postman’s features, you can efficiently test, debug, and document your SOAP web services. Remember to use collections for better organization and share your work to promote collaborative testing efforts.

API Testing Blog