Where do I set character encoding in SOAPUI Preferences

You may choose either of the following approach.

Changing the defualt encoding

1. Go to SOAPUI_HOME/bin.
2. Open soapui.bat/.sh, depending on your platform.
3. You should be able find JAVA_OPTS, then you can add there below line in a new line set JAVA_OPTS=%JAVA_OPTS% -Dfile.encoding="iso-8859-1" on windows
   export JAVA_OPTS=$JAVA_OPTS -Dfile.encoding="iso-8859-1" on unix
4. Save the file, start SoapUI.

It should take default encoding as iso-8859-1.

Alternatively, message specific:

Otherwise, you may use message specific character encoding using http headersfor that specific one in the following way:

Set a new header for request / response.
Header Key/name:Content-Type
Header Value :text/xml; charset=iso-8859-1

To set up an encoding for request/response you have to mark it in Navigator. Then in the view under the navigator go to "Request/Response properties" choose encoding and set i.e. to UTF-8 or iso-8859-1.