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.

25 hosts · 215 ms

HostCertsFirst seenLast seen
base64.ai 3 2026-05-19 2026-09-06
apidoc.base64.ai 3 2026-06-09 2026-08-09
dashboard.base64.ai 3 2026-05-20 2026-09-05
ultimate.base64.ai 1 2026-08-27 2026-08-27
kibana.ultimate.base64.ai 1 2026-08-27 2026-08-27
integrate.ultimate.base64.ai 1 2026-08-27 2026-08-27
ldap.ultimate.base64.ai 1 2026-08-27 2026-08-27
mcp.ultimate.base64.ai 1 2026-08-27 2026-08-27
integrate.base64.ai 4 2026-06-01 2026-09-18
staging.integrate.base64.ai 4 2026-06-01 2026-09-18
labeling.base64.ai 6 2026-04-24 2026-10-04
api.base64.ai 3 2026-06-06 2026-09-22
dev.api.base64.ai 3 2026-04-30 2026-08-17
llm.base64.ai 5 2026-04-12 2026-09-23
help.base64.ai 2 2025-06-18 2026-06-05
dashboards.base64.ai 3 2026-05-20 2026-09-05
pages.base64.ai 8 2026-05-08 2026-09-03
partners.base64.ai 11 2026-06-03 2026-09-30
wordpress.base64.ai 4 2026-04-25 2026-10-07
status.base64.ai 2 2026-09-30 2026-09-30
support.base64.ai 3 2026-05-20 2026-09-05
test.base64.ai 3 2026-05-08 2026-08-27
dev.base64.ai 3 2026-05-09 2026-08-29
wordpress.dev.base64.ai 3 2026-05-09 2026-08-29
www.base64.ai 3 2026-05-19 2026-09-06

Programmatic access: API GET /v1/hosts/base64.ai (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/base64.ai.