I have a use case to create a customer, with additional contact details and its medium as well.
But as per TMF 629, I am not able to get the placeholder to add the additional contact details while creating a new customer.
Can the customer resource can be extended to add sub resource Contact like below, along with other sub resource?
or any other way to add those additional contact details for customer?
I don't think you need the Contact subentity. Customer already has a list of contactMedium, which you can populate as part of POST (create) and PATCH (update).