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.

48 hosts · 350 ms

HostCertsFirst seenLast seenDNS
resend.com 10 2026-04-29 2026-09-03 ok
*.resend.com 6 2025-11-12 2026-09-03 —
sb.resend.com 8 2026-05-06 2026-09-01 ok
forward.resend.com 3 2026-06-08 2026-08-07 ok
unsubscribe.resend.com 5 2026-05-13 2026-09-14 ok
dub-unsubscribe.resend.com 5 2026-05-02 2026-09-05 ok
resend-unsubscribe.resend.com 4 2026-04-15 2026-08-16 ok
anghami-unsubscribe.resend.com 4 2026-04-20 2026-08-23 ok
basewell-unsubscribe.resend.com 5 2026-05-11 2026-09-14 ok
markprompt-unsubscribe.resend.com 5 2026-05-07 2026-09-08 ok
sb-staging.resend.com 8 2026-04-27 2026-08-23 ok
billing.resend.com 10 2026-04-22 2026-08-19 ok
blog.resend.com 5 2026-05-21 2026-09-22 ok
api.resend.com 12 2026-05-14 2026-09-09 ok
prosper-referral.resend.com 4 2026-04-11 2026-08-11 ok
waitlist-basewell.resend.com 5 2026-05-20 2026-09-23 ok
dreamteam.resend.com 5 2026-05-30 2026-09-29 ok
go.resend.com 4 2026-04-16 2026-08-15 ok
rio.resend.com 5 2026-05-25 2026-09-28 ok
mcp.resend.com 6 2026-06-18 2026-08-16 ok
fp.resend.com 2 2025-10-30 2026-09-30 ok
smtp.resend.com 3 2025-10-08 2026-09-08 ok
whois.resend.com 4 2026-06-03 2026-10-03 ok
emails.resend.com 5 2026-04-25 2026-08-27 ok
*.apps.resend.com 5 2026-06-18 2026-09-03 —
guardian-gate-api-grpc.apps.resend.com 3 2026-09-03 2026-09-03 nxdomain
iep-internal-api-grpc.apps.resend.com 2 2026-06-23 2026-06-23 ok
inboxes-internal-api-grpc.apps.resend.com 12 2026-08-18 2026-08-18 nxdomain
schedule-service.apps.resend.com 1 2025-12-21 2025-12-21 ok
canary-node.apps.resend.com 2 2026-07-15 2026-07-17 ok
api.apps.resend.com 1 2025-11-30 2025-11-30 ok
anti-abuse-api.apps.resend.com 4 2026-05-15 2026-05-19 ok
guardian-gate-api.apps.resend.com 3 2026-09-03 2026-09-03 ok
iep-internal-api.apps.resend.com 7 2026-04-06 2026-09-08 ok
email-api.apps.resend.com 1 2025-11-23 2025-11-23 ok
iep-email-api.apps.resend.com 4 2026-08-10 2026-08-11 ok
stars-api.apps.resend.com 1 2026-05-13 2026-05-13 ok
kafka-ui.apps.resend.com 1 2025-12-22 2025-12-22 nxdomain
remote-mcp.apps.resend.com 2 2026-06-18 2026-06-18 ok
smtp.apps.resend.com 2 2025-10-08 2026-09-08 ok
api-cf-backup.apps.resend.com 1 2025-11-18 2025-11-18 nodata
smtp-checker.apps.resend.com 1 2025-12-10 2025-12-10 ok
unified-sending-sender-consumer.apps.resend.com 1 2025-12-30 2025-12-30 nxdomain
unified-sending-router-consumer.apps.resend.com 1 2025-12-30 2025-12-30 nxdomain
secret-scanner.apps.resend.com 13 2026-03-05 2026-08-06 ok
status.resend.com 2 2025-07-25 2026-06-25 ok
weeklyupdate-markprompt.resend.com 5 2026-05-23 2026-09-26 ok
www.resend.com 5 2026-05-29 2026-09-27 ok

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