Partica supports subscription expiry dates for users stored in Auth0. The expiry date is stored in the app_metadata user field in Auth0. The user does not have access to modify the app_metadata field. See Auth0 documentation on metadata for more information.
Partica stores the expiry date in the following format dd-MMM-yyyy, e.g. for a user whose subscription expires on the 1st of January 2020 the expiry value would be 1-Jan-2020.
You can see this value under the user in the Auth0 dashboard.
You can create/update a users app_metadata via the Auth0 API.
The basic flow here is
If the user does not exist, do something.
If the user exists and has app_meatdata, merge the expiry value into the app_metatdata field.
If the user exists and does not have app_meatdata, create the app_metatdata with expiry.
You will need to perform some setup on Auth0 before using the API.