.us
Availability-check reliability and the registry servers we query for .us domains.
Our answer rate
Not enough data Country- Answer rate
- 100.0% of attempted checks returned a definitive answer
- Check volume
- Minimal (coarse band, not a count)
- Mostly answered by
- DNS
- Still available
- 88.4% of answered .us candidates were unregistered
- Last definitive answer
- 2026-09-21
Servers we query for .us
Public registry infrastructure — a whois, a
dig NS us, and one read of
IANA’s bootstrap file
return the same three values. Listed here for convenience.
- WHOIS host
-
whois.nic.us - Authoritative nameservers
-
w.cctld.us37.209.192.15x.cctld.us37.209.194.15y.cctld.us37.209.196.15b.cctld.us156.154.125.70f.cctld.us209.173.58.70k.cctld.us156.154.128.70m.cctld.us204.74.105.1n.cctld.us204.74.107.1 - RDAP endpoint
- no RDAP server — .us is checked by DNS / WHOIS
What this measures: the share of our own availability checks that came back with a definitive answer. Nobody else publishes this, because nobody else is running bulk registry lookups at this scale and recording what came back.
What it does not measure: a registry’s uptime or quality. A low rate here can just as easily mean our requests are being rate-limited as it can mean anything about the registry itself.
These are current-state figures, not a history. We keep one record per domain, holding its most recent check — so a TLD that failed hundreds of times and then recovered reads as healthy here. A low rate means checks are failing now; a high one does not mean they always have.
Figures count domains checked, not queries — a domain checked six times counts once. Candidates we generated but never checked are excluded entirely; they are not failures. Snapshot rebuilt 2026-09-27 02:19:47.