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.io domain: registry, rules and WHOIS

Software products, developer tools, start-ups

Facts

Type
Country-code TLD (ccTLD), used generically
Registry operator
Internet Computer Bureau (part of Identity Digital)
Country or territory
British Indian Ocean Territory
Added to the root zone
1997
RDAP
Not listed in the IANA bootstrap file
WHOIS server
whois.nic.io
Registration
Open to anyone
Typical use
Software products, developer tools, start-ups

RDAP availability is taken from the IANA RDAP bootstrap file published on 2026-09-16; WHOIS server and delegation year from the IANA root zone database. Registry policies change: check the registry's own policy before relying on an eligibility rule.

What is .io?

.io is the country-code top-level domain assigned to the British Indian Ocean Territory. Because "I/O" is shorthand for input/output, it was adopted by software companies, developer tools and start-ups, and today it is used almost entirely as a generic extension. Technically it remains a ccTLD: its policies are set by its manager, not by ICANN contracts that bind gTLDs.

Who can register it

Second-level .io names can be registered by anyone, with no local presence requirement.

WHOIS, RDAP and privacy

.io is not listed in the IANA RDAP bootstrap file dated 2026-09-16, so no public RDAP service is announced for it. OrbitProbe falls back to the classic port-43 WHOIS server (whois.nic.io). WHOIS output is free text in a registry-specific layout, so only a fixed set of fields is read (registrar, dates, status, nameservers) and some of them may simply not be present. For ccTLDs, what is published is decided by the registry and local law rather than by ICANN, so output differs from one extension to the next. Most registries do not show the personal data of individuals in public output. OrbitProbe only ever shows the organisation name and country.

Look up a .io domain

FAQ

Who can register a .io domain?

Second-level .io names can be registered by anyone, with no local presence requirement.

How do I run a WHOIS lookup for a .io domain?

Type the name, in the form example.io, into the form on this page. Because no RDAP service is published for .io, OrbitProbe queries the WHOIS server whois.nic.io. The result shows where the data came from and when it was observed.

Does .io support RDAP?

The IANA RDAP bootstrap file dated 2026-09-16 does not list an RDAP service for .io. Registration data is queried through the classic WHOIS server whois.nic.io. Registries can add RDAP later, so this may change over time.

Is .io a generic or a country-code domain?

.io is formally the country-code TLD assigned to British Indian Ocean Territory; being used like a generic one does not change that. The practical consequence is that registration, privacy and dispute rules are set by the manager of the TLD rather than by ICANN's gTLD contracts.