Dynamic API Request

Hello,

Is there a way to let users select parameter values for API requests?

The URL below does a look-up in an external database and returns a price...

"https://www.valucalc.com/pricequery.php?CutType=Round Brilliant&Weight=1.25&Quality=VS1&Color=D"

While I can hardcode it in PHPRunner's API request builder, I need a way to make it dynamic, depending on a user's selections at runtime.

https://customdataservices.net/lookup.gif

Any ideas?