Find every subdomain
of a domain.

Every hostname under a domain that ever appeared in a public TLS certificate — with certificate counts, first/last seen and live DNS status.

22 hosts · 273 ms

HostCertsFirst seenLast seenDNS
nyct.com 63 2025-09-08 2026-10-06 nodata
*.nyct.com 63 2025-09-08 2026-10-06 —
C620.nyct.com 1 2025-09-02 2025-09-02 —
AFC3.nyct.com 1 2025-09-02 2025-09-02 —
MTALPDC365CH07.nyct.com 5 2025-09-08 2026-09-15 —
MTA2BWY365CH07.nyct.com 5 2025-09-08 2026-09-15 —
MTALPDC365CH08.nyct.com 5 2025-09-08 2026-09-15 —
MTA2BWY365CH08.nyct.com 5 2025-09-08 2026-09-15 —
mtabase.glb.nyct.com 4 2025-09-08 2026-09-09 nxdomain
mtabase-dr.glb.nyct.com 4 2025-09-08 2026-09-09 nxdomain
bcchub.nyct.com 6 2026-04-10 2026-09-09 ok
bsm.nyct.com 6 2026-04-10 2026-09-09 ok
autodiscover.nyct.com 6 2025-08-12 2026-09-15 ok
*.transit.nyct.com 7 2025-09-08 2026-09-15 —
mtalivpadlds03.transit.nyct.com 4 2025-09-08 2026-09-09 nxdomain
mta2bwypadlds03.transit.nyct.com 4 2025-09-08 2026-09-09 nxdomain
mtalivpadlds04.transit.nyct.com 4 2025-09-08 2026-09-09 nxdomain
mta2bwypadlds04.transit.nyct.com 4 2025-09-08 2026-09-09 nxdomain
mtabase.transit.nyct.com 4 2025-09-08 2026-09-09 nxdomain
adlds03bwytadbk.transit.nyct.com 4 2025-09-08 2026-09-09 nxdomain
adlds04bwytadbk.transit.nyct.com 4 2025-09-08 2026-09-09 nxdomain
mymtakw.nyct.com 2 2026-09-28 2026-09-28 ok

Programmatic access, with DNS A records: API GET /v1/hosts/nyct.com (API key for paging).

Shown here: hostnames with a certificate that is valid now or expired within the last 90 days. The full history since 2013 — hostnames whose last certificate expired earlier — is a Pro plan method: GET /v1/hosts-history/nyct.com.