Take care to register the d/DOMAIN object for both itself and WWW, like i.e.:
{"ip":"1.2.3.4","map":{"www":{"ip":"1.2.3.4"}}}
If I'm not using A-record, but I'm using CNAME record:
{"alias":"my_ddns.domain.com."}
What should I do, in this case?
{"alias":"my_ddns.domain.com.","map":{"www":{"alias":"my_ddns.domain.com."}}}
Right?
Yeah, should also work fine.
Using "map":{"*": ... you can furthermore match any subdomain with the wildcard.