How to organize the transfer of commands and data between Mikrotik and an external server?

Question

Mikrotik

I am making a captive portal on a vds server. Needed for authorization of Wi-Fi users, which distributes Mikrotik.
Those. when a user connects to the network, Mikrotik will redirect him to the page of an external vds server, where the user logs in, and the server will issue a command to Mikrotik to provide the Internet to the user.
Got a question. How can I do this very transfer of commands to Mikrotik from the server? If anything, Mikrotik does not have a white ip.

Answer 1

With the help of scripts, cron. Mikrotik has options for this.
On the server, you make an api that will give the user's status, and Mikrotik requests and performs the necessary actions.
How? There are enough examples of scripts on the Mikrotik website

Answer 2

Mikrotik has a built-in hotspot. Which can do a lot of things, including Radius
Do it right through the built-in hotspot

Answer 3

HotSpot on Mikrotik with SMS authorization for compliance...