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.

3 hosts · 196 ms

HostCertsFirst seenLast seenDNS
data.newsletter.avianca.com 4 2025-09-08 2026-09-10 ok
cdn.newsletter.avianca.com 1 2026-02-18 2026-02-18 ok
pages.newsletter.avianca.com 5 2025-09-24 2026-09-26 ok

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