Can I use the response body of an HTTP request and create a variable server side?
No, there are no such variables. You can only use the reponse only as part of the tag’s work.
can you point me in the right direction on resources that I can read about how I can use the reponse as part of the tag’s work?
Could you elaborate on your requirement a little bit?
In abstract there are two things:
a) you can use http-lookup variable: GitHub - stape-io/http-lookup-variable: HTTP Lookup Variable for Google Tag Manager Server Side to send a request outward and extract response data for use in other tag(s)
if that doesn’t fit your situation then
b) you need to contain all the logic (of sending a hit and then using response data for another one) within confines of one tag template