var api = new NameCheapApi("{username}", "{apiUser}", "{apiKey}", "{clientIp}", isSandbox: false);

var domains = api.Domains.AreAvailable("google.com", "ANewDomainName");

foreach (var domain in domains)
    Console.WriteLine(domain.DomainName + ": " + domain.IsAvailable);

var api = new NameCheapApi("{username}", "{apiUser}", "{apiKey}", "{clientIp}", isSandbox: true);
 
api.Dns.SetHosts(
    new DnsHostsRequest
    {
        SLD = "YourDomainName",
        TLD = "com",
        HostEntries = new HostEntry[] { new HostEntry() { 
            Address = "192.168.1.1",
            HostName = "@",
            RecordType =  RecordType.A
        } }
    });