Yes, you can. CFLOW lets you integrate to any external web service and get the values from that web service and populate the return values to fields in your form. You can do all this without writing a single line of code.
Specify the web service properties to integrate to the external web service of your choice. Ensure that you specify the parameters correctly and select the fields that need to be populated.
During execution, when a value is entered in the triggering field and you move to the next field, the web service is executed and the other fields are populated as configured.
Here is an example of the web service configuration for temperature conversion.