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.

23 hosts · 327 ms

HostCertsFirst seenLast seenDNS
steplab.co 85 2025-09-10 2026-10-06 ok
*.steplab.co 43 2025-09-10 2026-09-29 —
static.steplab.co 2 2025-06-20 2026-05-20 ok
worker-ghostmiddleware.steplab.co 14 2026-04-12 2026-10-06 ok
institute.steplab.co 58 2026-04-13 2026-08-25 ok
ludwig.steplab.co 8 2026-05-01 2026-08-28 ok
connection-check.steplab.co 8 2026-04-19 2026-08-16 ok
app.steplab.co 1 2026-01-29 2026-01-29 ok
*.app.steplab.co 17 2025-09-10 2026-09-26 —
flower.app.steplab.co 1 2025-07-14 2025-07-14 nxdomain
webhookhandler.steplab.co 6 2026-06-21 2026-08-19 ok
*.webhookhandler.steplab.co 6 2026-06-21 2026-08-19 —
hubs.steplab.co 28 2026-04-09 2026-10-01 ok
resources.steplab.co 2 2025-06-25 2026-05-26 ok
deeplinks.steplab.co 6 2026-05-01 2026-08-27 ok
*.deeplinks.steplab.co 6 2026-05-01 2026-08-27 —
events.steplab.co 74 2026-04-26 2026-10-01 ok
aus.steplab.co 1 2026-01-29 2026-01-29 ok
hubs-aus.steplab.co 34 2026-06-08 2026-08-25 ok
*.aus.steplab.co 17 2025-09-10 2026-09-26 —
flower.aus.steplab.co 1 2025-07-16 2025-07-16 nxdomain
support.steplab.co 8 2026-05-06 2026-09-02 ok
security.steplab.co 12 2026-05-24 2026-09-20 ok

Programmatic access, with DNS A records: API GET /v1/hosts/steplab.co (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/steplab.co.