When working on one of the workflow development tasks, it was required to have a web service call to fetch data from SharePoint. To do that I used a "Call HTTP web service" action but with that I was getting the following exception “Unable to de-serialize HTTP response content. Expected Content Type: 'application/json', 'text/plain' or 'text/html'”.



After struggling with this issue, the solution I used thought to share the solution with the developer community.

Solution: The reason for the issue is, by default response from SharePoint REST is in XML and the SharePoint designer workflow is not able to parse the XML and needs a JSON response. To resolve this issue we need to pass Accept and Content-Type as application/json;odata=verbose to request the headers. This way we will get a JSON response. To resolve this use the following procedure.
  1. Go to SharePoint 2013 designer.

  2. Build a Dictionary variable named "WSHearder".



  3. Add two values in the newly created dictionary.

    Accept = application/json;odata=verbose

    Content =Type = application/json;odata=verbose



  4. Now select a "Call HTTP web service" action and select Properties.



  5. Select the newly created dictionary variable as value for "".



  6. Press OK and publish the workflow.