Matthew, the documentation ends with the instruction to 'use a
library'...
I have taken JWT.php, uploaded it to the root of my site and required
it once in my postback.php.
I don't any documentation for that step or any after that!
I've used the 'In-App Payments demo' to get my javascript
'goog.payments.inapp.buy' and encode my jwt.
I must also note that the documents provided do not even show a list
of 'Uh oh' errors and their possible causes!
Well Un-documented I would say as to be honest Matthew I don't know
what problem I'm having with jwt I now know how to properly pronounce
jwt (as jot), I fail to answer you, I just don't know!
Maybe you could lead me to the well documented part...?
https://developers.google.com/in-app-payments/docs/tutorial
https://developers.google.com/in-app-payments/docs/postback