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.

41 hosts · 348 ms

HostCertsFirst seenLast seenDNS
semafor.com 4 2026-04-07 2026-08-05 ok
www-stage-lb.semafor.com 3 2026-05-23 2026-09-06 ok
api-lb.semafor.com 5 2026-04-14 2026-09-24 ok
www-lb.semafor.com 5 2026-04-12 2026-09-25 ok
static.semafor.com 7 2026-06-12 2026-09-20 ok
stage.semafor.com 4 2026-04-07 2026-08-05 ok
api-lb-stage.semafor.com 3 2026-05-22 2026-09-12 ok
static-stage.semafor.com 5 2026-05-24 2026-09-21 ok
img-stage.semafor.com 4 2026-04-21 2026-08-19 ok
api-stage.semafor.com 1 2026-04-13 2026-04-13 ok
soup-stage.semafor.com 3 2026-05-08 2026-08-26 ok
preview-stage.semafor.com 3 2026-04-24 2026-08-14 ok
*.stage.semafor.com 6 2026-05-16 2026-08-27 —
data.stage.semafor.com 1 2026-08-28 2026-08-28 ok
api.stage.semafor.com 5 2026-06-02 2026-09-30 ok
img-io.stage.semafor.com 3 2026-08-28 2026-09-17 ok
img.semafor.com 4 2026-04-21 2026-08-19 ok
sli.semafor.com 2 2025-06-16 2026-05-17 ok
t-mini.semafor.com 4 2026-04-11 2026-08-08 ok
api.semafor.com 4 2026-04-13 2026-08-11 ok
email.semafor.com 5 2026-05-26 2026-09-22 ok
go.semafor.com 5 2026-05-07 2026-09-22 ok
img-io.semafor.com 3 2026-08-28 2026-09-17 ok
signup.semafor.com 8 2026-04-09 2026-09-26 ok
soup.semafor.com 3 2026-04-21 2026-08-10 ok
newsletter-audience-manager.semafor.com 16 2026-05-17 2026-08-27 ok
tools.semafor.com 4 2026-06-03 2026-09-16 ok
signup-tokens.semafor.com 16 2026-05-17 2026-08-27 ok
events.semafor.com 8 2026-04-17 2026-08-19 ok
t.semafor.com 3 2026-05-21 2026-09-08 ok
dev.semafor.com 7 2026-06-20 2026-09-28 ok
www-lb-dev.semafor.com 3 2026-04-27 2026-08-16 ok
static-dev.semafor.com 4 2026-04-08 2026-08-06 ok
api-dev.semafor.com 2 2026-06-30 2026-08-25 ok
soup-dev.semafor.com 3 2026-05-12 2026-08-29 ok
preview-dev.semafor.com 3 2026-04-28 2026-08-11 ok
*.dev.semafor.com 11 2026-05-02 2026-08-18 —
api.dev.semafor.com 6 2026-06-07 2026-09-15 ok
img-io.dev.semafor.com 4 2026-08-28 2026-09-17 ok
preview.semafor.com 4 2026-04-14 2026-09-23 ok
www.semafor.com 5 2026-04-06 2026-10-03 ok

Programmatic access, with DNS A records: API GET /v1/hosts/semafor.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/semafor.com.