.co
Availability-check reliability and the registry servers we query for .co domains.
Our answer rate
Good Country- Answer rate
- 100.0% of attempted checks returned a definitive answer
- Check volume
- Medium (coarse band, not a count)
- Mostly answered by
- DNS
- Still available
- 88.9% of answered .co candidates were unregistered
- Last definitive answer
- 2026-09-21
Servers we query for .co
Public registry infrastructure — a whois, a
dig NS co, and one read of
IANA’s bootstrap file
return the same three values. Listed here for convenience.
- WHOIS host
-
whois.registry.co - Authoritative nameservers
-
a.registrydns.co194.169.218.57b.registrydns.co185.24.64.57c.registrydns.co212.18.248.57d.registrydns.co212.18.249.57 - RDAP endpoint
- no RDAP server — .co 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.