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.

11 hosts · 285 ms

HostCertsFirst seenLast seenDNS
textfree.us 26 2026-04-21 2026-09-22 ok
*.textfree.us 10 2026-04-21 2026-09-22 —
links.mail.textfree.us 3 2025-07-23 2026-08-17 nxdomain
links.info.textfree.us 6 2025-07-20 2026-09-26 ok
qa01-messages.textfree.us 1 2025-11-23 2025-11-23 nodata
*.qa01-messages.textfree.us 1 2025-11-23 2025-11-23 —
stage01-messages.textfree.us 1 2026-01-12 2026-01-12 nodata
*.stage01-messages.textfree.us 1 2026-01-12 2026-01-12 —
dev01-messages.textfree.us 2 2025-10-26 2026-09-26 ok
*.dev01-messages.textfree.us 2 2025-10-26 2026-09-26 —
www.textfree.us 16 2026-04-21 2026-08-17 ok

Programmatic access, with DNS A records: API GET /v1/hosts/textfree.us (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/textfree.us.