Can we curl or similar to get string values from APIs at the point Mural opens

I have a Mural and I would like it to get the latest exchange rate (or stock information or anything else). The value would live in a post it note - I'm not expecting to do anything with the value other than read it (meaning, I'm not going to attempt a calculation)

I don't want to have to write a python script because, if I've understood the docs correctly, I would have to run the script every time I wanted to load the Mural

My ideal work flow is open Mural, and the post it note which curls/references a get API endpoint returns the string and inserts that string into the post it note.

I can't see if this is possible