Check-Host.cc

Top-Level Domain

.io

Aggregated statistics for the top-level domain

Apex domains
695,782
we've enumerated
Subdomains seen
9,487,961
CT + DNS + brute
TLS certs
83,121
naming .io
Hosting ASNs
15
distinct origins

Domain Distribution

Apex domains with the most known subdomains — large orgs, telecoms, hosters.
Apex Subdomains
azurecontainerapps.io 3,459,555
keenetic.io 1,821,302
nip.io 330,080
sslip.io 266,422
azurecontainerapps-test.io 186,089
k4apps.io 174,661
nid.io 118,143
netcraze.io 87,393
starsweb.io 74,090
tktl.io 64,702
qzz.io 52,285
instruqt.io 30,428
nxcli.io 26,942
cloudhub.io 22,489
jsdelivr.io 19,471
aroapp-hcp.io 13,742
redhatworkshops.io 12,730
streamgpu.io 11,899
aroapp.io 11,704
cedevice.io 10,053
isccloud.io 9,103
tmachine.io 8,450
sfmc.io 8,262
wiz.io 7,956
upli.io 7,576
ikarem.io 7,457
icore.io 6,908
cxnpl.io 6,579
affiliatereel.io 6,089
galaxy-dev.io 5,403
cs-ide.io 5,113
azmk8s.io 5,108
cwan.io 4,892
lumar.io 4,787
fluffy-otter-5.telebit.io 4,774
sapcloud.io 4,768
enablon.io 4,686
backname.io 4,685
pegcloud.io 4,401
hotelengine.io 4,383
serious-cat-33.telebit.io 4,353
litegallery.io 4,292
gigantic.io 4,250
zuddl.io 4,226
wdr.io 4,192
ordinary-elephant-58.telebit.io 4,059
dishcloud.io 3,945
enotis.io 3,884
amazee.io 3,859
idemia.io 3,802

Top Certificate Issuers

Issuer (CA) Certs
Amazon 29,667
Let's Encrypt 24,325
WR3 5,216
ca 4,997
YR1 1,932
YR2 1,865
YE2 1,784
YE1 1,699
Sectigo 1,678
RunCloud WebSSL Root CA 1,578
DigiCert 1,367
Cloudflare 1,232
GoDaddy 714
ZeroSSL 437
GlobalSign 367

Top Hosting ASNs

ASN Name .io domains
AS16509 Amazon.com 356,409
AS8075 Microsoft 322,852
AS13335 Cloudflare 134,591
AS396982 Google Cloud 60,836
AS14061 DigitalOcean 56,790
AS24940 Hetzner Online 55,779
AS16276 OVHcloud 36,548
AS214996 26,719
AS14618 Amazon AES 23,436
AS49505 Selectel Ltd. 22,513
AS41722 Miran 17,819
AS206834 16,931
AS47583 Hostinger International 16,647
AS54113 Fastly, Inc. 14,599
AS34762 Combell 12,970

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.