Use field API key in emails

I would like to send a pre-filled form with Google Forms and for that purpose, I am trying to figure out if it is possible to use the field API keys of certain fields I need in an email.

Here is what the URL looks like for Google Forms:

I am trying to dynamically replace firstname and lastname in the URL.

Please let me know.

Does anybody have any ideas on the syntax I can use? This is all I need to give it a try.

Hi. Did you ever get anywhere with this? I’ve got the same issue. Thanks Brad