You can now create subdomains for your domain.
If you have "test.f5.si", you can use this feature to create sub-subdomains like "web.test.f5.si",
You can create sub-sub-subdomains such as "a.web.test.f5.si".
In addition to the settings screen, you can also use the HTTP API.
https://ddns.kuku.lu/setupinfo.php The record types available for subdomains are A/AAAA/TXT/CNAME.
You can create up to 10 subdomains per account.