Surprisingly I could neither find any hints in the documentation (neither the official one, not at zeraton) about using the API to update singleton data.
From checking the requests sent when updating a singleton from the admin interface, I figured out that it is using the
singletons/update_data/singleton_name-endpoint. This however seems to be protected behind login. Using it without logging in just results in a redirect, to the authentication page.
Is there any way to update singleton data via the API, or is it just not possible currently?