Since CMD_API calls usually mirror CMD_ calls, the command: CMD_SUBDOMAIN had the API: CMD_API_SUBDOMAINS with an "S" at the end, which could cause confusion. I've added an alias: CMD_API_SUBDOMAIN so that both CMD_API_SUBDOMAIN and CMD_API_SUBDOMAINS will work. Example: http://files.directadmin.com/services/all/httpsocket/examples/example.add_subdomain.php