You are using a third-party authentication provider and would like to automate user signup/registration in the DNN portal. To do the same, you would like to know if there is a specific DNN API that you can call which will insert a record in DNN DB without using the front-end signup process and how that API works.
Currently, there is no DNN API exposed on the client-side to perform user registration. DNN registration is handled by the ASP.NET Membership Provider and uses a secure .NET form, which can be confirmed by the fact that data from the registration form contains form elements that have unique IDs depending on the session.
Note: AspNetMembershipProvider is not a DNN-specific component but a Microsoft component. For further information, please refer to How to: Use the ASP.NET Membership Provider.
To achieve the desired result, you would have to create a custom solution via a script or code-based API, which is out of DNN Support Team scope. However, you can find more information in the following links:
- Adding users and roles programmatically using DNN API: a discussion that relates to the topic and suggests simply adding users using SQL - this can be done via a custom script that receives input through an endpoint exposed like an API.
- Create User Programmatically in DotNetNuke and How to create custom registration module in DotNetNuke both provide a code-based approach to do this in C#.
- Creating your own Authentication Provider also takes a code-based approach in order to create a custom module.
If you are interested in developing this custom module, you can contact your Account Manager to discuss an engagement with the DNN Professional Services team whereby this can possibly be taken up as a custom project. They will discuss your requirements and provide a statement of work with the expected cost for the same if it is feasible.
Alternatively, there are third-party providers who offer custom DNN development services that you may want to explore, such as DNN Sharp.