On several of the fields in the nest api docs, I see examples with "STRING1" and "STRING2" in the URL which are described as "do not change", do I need to include those in requests, or what are those for?
In most cases, STRING1/2 are returned when you read the device values. You'll pass them along when you use the URL.
For example, when I read my camera, I get this response:
"image_url": "https://www.dropcam.com/api/wwn.get_image/CjZRcWll.../OwKxchf...?auth=c.twC2qlu...",
In this example, STRING1 = CjZRcWll...
and DEVICE_ID = OwKxchf
I can copy the "https://...
" string, paste it into a web browser and see the image that was captured.