Please note:
The docs refer to badgr-io’s API v1.
Badgr changed its API to v2 and broke the functionality in 2018.
You need to self host badgr server, badgr-io’s self hosting code, and do a couple of quick changes.
I describe them here Error updating user preferences. Credentials not provided?
I am hoping badgr-server isn’t updated to v2 at any point.