Check-Host.cc

Top-Level Domain

.io

Aggregated statistics for the top-level domain

Apex domains
769,331
we've enumerated
Subdomains seen
12,781,286
CT + DNS + brute
TLS certs
96,549
naming .io
Hosting ASNs
15
distinct origins

Domain Distribution

Apex domains with the most known subdomains — large orgs, telecoms, hosters.
Apex Subdomains
azurecontainerapps.io 4,866,920
keenetic.io 2,153,866
netcraze.io 730,889
nip.io 452,755
sslip.io 393,344
azurecontainerapps-test.io 260,017
k4apps.io 253,814
nid.io 118,143
starsweb.io 75,059
tktl.io 65,342
qzz.io 63,362
instruqt.io 36,996
nxcli.io 32,155
cloudhub.io 24,213
streamgpu.io 20,900
jsdelivr.io 19,471
isccloud.io 17,545
aroapp-hcp.io 17,256
aroapp.io 15,622
redhatworkshops.io 14,954
azmk8s.io 10,862
tmachine.io 10,712
sfmc.io 10,320
cedevice.io 10,306
wiz.io 7,956
upli.io 7,855
ikarem.io 7,845
cs-ide.io 7,386
galaxy-dev.io 7,178
icore.io 6,809
cxnpl.io 6,676
affiliatereel.io 6,391
sapcloud.io 5,440
zuddl.io 5,434
fluffy-otter-5.telebit.io 5,299
pegcloud.io 5,081
backname.io 5,013
cwan.io 4,917
amazee.io 4,841
wdr.io 4,818
lumar.io 4,803
enablon.io 4,768
serious-cat-33.telebit.io 4,670
litegallery.io 4,629
azgrafana.io 4,610
sehlat.io 4,585
cloudezapp.io 4,488
hotelengine.io 4,388
gigantic.io 4,361
enotis.io 4,251

Top Certificate Issuers

Issuer (CA) Certs
Amazon 29,848
Let's Encrypt 25,087
ca 10,717
WR3 6,518
YR1 2,917
YE2 2,861
YR2 2,754
YE1 2,712
Sectigo 1,844
RunCloud WebSSL Root CA 1,778
DigiCert 1,505
Cloudflare 1,418
GoDaddy 783
ZeroSSL 520
GlobalSign 411

Top Hosting ASNs

ASN Name .io domains
AS16509 Amazon.com 403,396
AS8075 Microsoft 376,699
AS49505 Selectel Ltd. 180,834
AS13335 Cloudflare 161,316
AS41722 Miran 144,578
AS396982 Google Cloud 106,972
AS14061 DigitalOcean 67,879
AS24940 Hetzner Online 67,032
AS50340 Selectel MSK 56,722
AS16276 OVHcloud 43,035
AS214996 29,826
AS14618 Amazon AES 26,599
AS47583 Hostinger International 21,326
AS206834 20,870
AS54113 Fastly, Inc. 16,859

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 1,920
ℹ Coverage will improve significantly once CZDS zone-file access is granted for this TLD.