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.

6 hosts · 250 ms

HostCertsFirst seenLast seen
guestwifi.sainsburysargos.co.uk 2 2025-07-23 2026-08-05
pbag1dmzclpas01.guestwifi.sainsburysargos.co.uk 1 2026-08-05 2026-08-05
www.pbag1dmzclpas01.guestwifi.sainsburysargos.co.uk 1 2026-08-05 2026-08-05
www.guestwifi.sainsburysargos.co.uk 1 2025-07-23 2025-07-23
securewifilogin.sainsburysargos.co.uk 2 2026-04-10 2026-10-06
www.securewifilogin.sainsburysargos.co.uk 2 2026-04-10 2026-10-06

Programmatic access: API GET /v1/hosts/sainsburysargos.co.uk (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/sainsburysargos.co.uk.