I'm trying to log in using token based auth - in my sandbox account. first hurdle is that when i try and post to https://<account>_SB1.restlets.api.netsuite.com/rest/requesttoken - I can't even connect to it, like that url doesn't exist. do SB accounts use a different URL or something?

try using https://<account>-SB1 (- not _ )

thanks! that fixed it