Working with SOAP APIs

Introduction

Some systems still use SOAP APIs (Simple Object Access Protocol) instead of REST APIs. SOAP is a messaging protocol that uses XML in order to exchange information between computers.

At Locoia, you can integrate SOAP APIs by configuring Connector Actions with SOAP-specific settings.

Creating the SOAP Request Body

Define a valid SOAP XML payload manually in the Request Body Template using Jinja for dynamic fields.

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:web="http://webservice.example.com/">
   <soapenv:Header/>
   <soapenv:Body>
      <web:getDetails>
         <id>{{ id }}</id>
      </web:getDetails>
   </soapenv:Body>
</soapenv:Envelope>

✅ Ensure correct use of namespaces (xmlns) as per the API specification.

Endpoint Details

Reading Details from the WSDL

The WSDL (Web Services Description Language) file defines:

• Available operations (methods)

• Expected input and output formats

• Required namespaces and endpoints

Use the WSDL to:

• Identify operation names

• Understand the expected structure of requests

• Verify service URLs

📚 In SoapUI, importing the WSDL auto-generates method templates.

Reading Documentation from the XSD

The XSD (XML Schema Definition) describes:

• Data types (string, int, boolean)

• Field validations (e.g., minLength, maxLength)

• Mandatory and optional fields

XSDs are often referenced inside WSDLs and explain how the body structure should be composed.

Testing Requests

Testing with SoapUI

To read out all the endpoint details of a SOAP API, you can use a tool such as SoapUI (download SoapUI Open Source).

1. Create a new SOAP project

   1. Make sure that Create Requests is turned on. This way the tool will create sample requests for you with the correct structure, where you simply have to fill in the parameters.

      
2. Import the WSDL

   Load the WSDL file provided by the API. SoapUI will parse the available methods and message formats.

3. SoapUI generates available operations

   All available operations (endpoints) will appear automatically after importing the WSDL

4. Customize and send requests

   • Edit the generated XML request templates.

   • Insert the correct field values.

   • Set the SOAPAction manually if needed.

   
5. Review the full XML responses and faults

   • Inspect the returned XML.

   • Handle successful responses or SOAP faults properly.

Why use SoapUI?

✅ WSDL parsing

✅ Visual method explorer

✅ Automated request templates

Testing with Postman

To test the request in Postman, you can follow this article from Postman itself: Send SOAP requests

• Set method to POST

• Set Headers:

  • Content-Type: text/xml

  • SOAPAction (if needed)

  
• Paste the XML manually into the raw body

• Send a request and view the response

Testing directly inside Locoia

In case the SOAP web service requires the text/xml Content-Type, add it as a header to the Connector itself:

{
  "content_type": "text/xml"
}

In the actions, you always need to select post as the method and add the SOAPAction method name in the header.

The XML can be written directly into the request body template.

Parsing SOAP Responses

SOAP responses are XML. Extract values using:

• Jinja templating (e.g., regex_replace)

• Additional Flow steps for XML parsing if needed

Example Jinja Extraction:

{{ body | regex_replace('<id>(.*?)</id>', '\\1') }}

Special Notes

• Strict namespace usage is mandatory.

• Handle SOAP faults properly (<Fault> elements).

• Authentication varies depending on API (Basic Auth, API Key, OAuth).