How to create a free domain registration service?

Question

Domain name market

I welcome those who are interested :)
Actually, the whole topic is stated in the title.
If anyone has experience in this niche, then I would like to know all aspects of the issue: technical, legal and financial.
With domains, I'm on "you", but now I want to master this topic and create a service for registering third-level domains in the ".kz" zone. This is for bloggers and small businesses. There are free hostings, but there are no domains.
I heard that it is supposedly very difficult to create such a service, etc., but no one specifically says anything. A service like this is sorely needed. The fact is that my friend and I created a tumblelog platform for KazNet tumble.kzand will soon enable the option to attach a domain to your tlog. So I would like to provide everything at once, but at the same time let the people use domains, even if they do not have a logo with us.

Answer 1

I tried. In principle, nothing complicated. First, write to the database, then upload to the zone of any DNS server * (for starters, once every 10 minutes), when there are many domains, the mechanism can be improved.
*) even in sqlite, powerdns, for example, can already do that.
Whois can be done very quickly on xinet.d

Answer 2

As I understand it, you just need to give users the opportunity to make an A-record for the 3rd level domain. Well, MX so that the mail goes.

Answer 3

From a technical point of view, when registering the xxx.tumble.kz domain, we ask what DNS servers the user wants to install, and put NS records on them.

www.tumble.kz IN NS ns1.yyy.kz.
www.tumble.kz IN NS ns2.yyy.kz.

You can also raise the whois server, and issue data about the owner of the domain there.
If we want to attract third-party registrars - API for registration.