How do VK auto-posting services work?

Question

API

In all services, only access to the application is given, and then they automatically post in our groups, to get the rights, just follow the link, and then the redirect occurs back to the site. In some, a code is requested by reference (response_type=code) and further on this code, as I understand it, they receive a token. For posting in groups, the server must have a standalone application. But there is one thing, redirect_uri does not work on such applications, there is a standard https://oauth.vk.com/blank.html. The question is how do they manage to post messages on the wall, if it is usually forbidden, that is, there are no rights.

Answer 1

I wrote a similar application, faced the same problem. To gain access to this method, we wrote to the TP and described our project, within a couple of days we were told that access was granted