Check-Host.cc

Top-Level Domain

.io

Aggregated statistics for the top-level domain

Apex domains
692,132
we've enumerated
Subdomains seen
9,402,056
CT + DNS + brute
TLS certs
82,467
naming .io
Hosting ASNs
15
distinct origins

Domain Distribution

Apex domains with the most known subdomains — large orgs, telecoms, hosters.
Apex Subdomains
azurecontainerapps.io 3,448,986
keenetic.io 1,801,057
nip.io 326,473
sslip.io 259,024
azurecontainerapps-test.io 185,582
k4apps.io 174,214
nid.io 118,142
netcraze.io 83,070
starsweb.io 73,902
tktl.io 64,511
qzz.io 51,426
instruqt.io 29,880
nxcli.io 26,700
cloudhub.io 22,330
jsdelivr.io 19,471
aroapp-hcp.io 13,710
redhatworkshops.io 12,580
streamgpu.io 11,875
aroapp.io 11,619
cedevice.io 10,030
isccloud.io 9,082
tmachine.io 8,288
sfmc.io 8,257
wiz.io 7,925
upli.io 7,557
ikarem.io 7,416
icore.io 6,907
cxnpl.io 6,558
affiliatereel.io 6,064
galaxy-dev.io 5,333
cs-ide.io 5,062
cwan.io 4,883
azmk8s.io 4,805
lumar.io 4,781
fluffy-otter-5.telebit.io 4,767
sapcloud.io 4,710
enablon.io 4,678
backname.io 4,664
hotelengine.io 4,383
pegcloud.io 4,353
serious-cat-33.telebit.io 4,301
litegallery.io 4,279
gigantic.io 4,239
zuddl.io 4,179
wdr.io 4,176
ordinary-elephant-58.telebit.io 3,969
dishcloud.io 3,944
enotis.io 3,857
idemia.io 3,798
amazee.io 3,798

Top Certificate Issuers

Issuer (CA) Certs
Amazon 29,660
Let's Encrypt 24,280
WR3 5,163
ca 4,697
YR1 1,889
YR2 1,818
YE2 1,744
Sectigo 1,669
YE1 1,648
RunCloud WebSSL Root CA 1,572
DigiCert 1,359
Cloudflare 1,220
GoDaddy 709
ZeroSSL 433
GlobalSign 363

Top Hosting ASNs

ASN Name .io domains
AS16509 Amazon.com 354,717
AS8075 Microsoft 321,975
AS13335 Cloudflare 133,484
AS396982 Google Cloud 59,387
AS14061 DigitalOcean 56,507
AS24940 Hetzner Online 55,276
AS16276 OVHcloud 36,329
AS214996 26,430
AS14618 Amazon AES 23,321
AS49505 Selectel Ltd. 21,336
AS41722 Miran 16,903
AS206834 16,822
AS47583 Hostinger International 16,485
AS54113 Fastly, Inc. 14,526
AS34762 Combell 12,825

Tech-Stack Distribution

No Wappalyzer detections

Body-fetcher hasn't covered enough .io sites yet for stack patterns to emerge.

Most-resolved apex domains

Apexes resolving to the most distinct A/AAAA records — popularity proxy.

Threat-intel hits

Feed Category Domains
openphish phishing 1,587
ℹ Coverage will improve significantly once CZDS zone-file access is granted for this TLD.