Find every subdomain
of a domain.

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

26 hosts · 290 ms

HostCertsFirst seenLast seen
tfx.tax 14 2025-07-23 2026-09-05
*.tfx.tax 14 2025-07-23 2026-09-05
servicedesk.jira.tfx.tax 2 2026-04-14 2026-09-14
webpage.tfx.tax 2 2026-08-04 2026-10-02
servicedesk.tfx.tax 2 2026-04-14 2026-09-14
bmhelp.tfx.tax 18 2026-04-13 2026-10-08
hz01-atxsh-10.corp.tfx.tax 10 2026-04-20 2026-09-14
hz01-rdsh-01.corp.tfx.tax 10 2026-04-20 2026-09-14
hz01-atxsh-01.corp.tfx.tax 10 2026-04-20 2026-09-14
bk01-rds-01.corp.tfx.tax 8 2026-04-13 2026-09-14
hz01-rds-01.corp.tfx.tax 10 2026-04-20 2026-09-14
hz01-rdsh-02.corp.tfx.tax 10 2026-04-20 2026-09-14
hz01-atxsh-02.corp.tfx.tax 10 2026-04-20 2026-09-14
bk01-rds-02.corp.tfx.tax 8 2026-04-13 2026-09-14
hz01-rds-02.corp.tfx.tax 10 2026-04-20 2026-09-14
hz01-rdsh-03.corp.tfx.tax 10 2026-04-20 2026-09-14
hz01-atxsh-03.corp.tfx.tax 10 2026-04-20 2026-09-14
hz01-atxsh-04.corp.tfx.tax 10 2026-04-20 2026-09-14
hz01-atxsh-05.corp.tfx.tax 10 2026-04-20 2026-09-14
hz01-atxsh-06.corp.tfx.tax 10 2026-04-20 2026-09-14
hz01-atxsh-07.corp.tfx.tax 10 2026-04-20 2026-09-14
hz01-atxsh-08.corp.tfx.tax 10 2026-04-20 2026-09-14
hz01-atxsh-09.corp.tfx.tax 10 2026-04-20 2026-09-14
backuprd.corp.tfx.tax 10 2026-04-20 2026-09-14
bk01.vpn.corp.tfx.tax 6 2026-04-14 2026-09-14
hz01.vpn.corp.tfx.tax 10 2026-04-20 2026-09-14

Programmatic access: API GET /v1/hosts/tfx.tax (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/tfx.tax.