Help with JSON validation in Kore

Hi Kore team, hope this message finds you well,

My team and I have a project in which we get information from a web service, then have the user enter information into a digital form.

We would like to know how we can do in Kore to perform a validation of the information entered in the form vs the information of the service (JSON).

Can this be done with a node script?
If the previous answer is yes, how could I call the variables of the node script to inform the user?

I attach an image with the process: