ASN & DNS Lookups in Go

Returns the ASN, owning organization, network range, and country for an IP — and whether it belongs to a datacenter. Nullable fields are pointers.

client := ipapi.NewClient(ipapi.WithAPIKey(os.Getenv("IP_API_IO_KEY")))
ctx := context.Background()

asn, _ := client.ASN(ctx, "8.8.8.8")

if asn.ASN != nil {
	fmt.Println(*asn.ASN)          // 15169
}
if asn.Organization != nil {
	fmt.Println(*asn.Organization) // "Google LLC"
}
fmt.Println(asn.IsDatacenter)      // true

WHOIS record for a domain: registrar, registration/expiry/update dates, name servers, status codes, and the raw WHOIS text.

whois, _ := client.Whois(ctx, "example.com")

if whois.Registrar != nil && whois.Registrar.Name != nil {
	fmt.Println(*whois.Registrar.Name)
}
if whois.RegisteredOn != nil {
	fmt.Println(*whois.RegisteredOn) // "1995-08-14"
}
fmt.Println(whois.NameServers)

Resolve a PTR record, resolve a hostname to addresses, or list a domain's mail servers.

rdns, _ := client.ReverseDNS(ctx, "8.8.8.8")
if rdns.Hostname != nil {
	fmt.Println(*rdns.Hostname) // "dns.google"
}

fdns, _ := client.ForwardDNS(ctx, "dns.google")
for _, record := range fdns.Addresses {
	fmt.Println(record.Type, record.Address, record.TTL) // "A" "8.8.8.8" 300
}

mx, _ := client.MXRecords(ctx, "example.com")
for _, record := range mx.MXRecords {
	fmt.Println(record.Priority, record.Hostname, record.TTL)
}