General
- Extension
- .io
- Type
- Country-code extension
- Meaning
- British Indian Ocean Territory
- Registry
- Internet Computer Bureau Limited
- Registry website
- www.nic.io
- Registered since
- 16 September 1997
Properties
- DNSSEC signed
- yes
- Name servers
- 4 (4 with IPv6)
- WHOIS server
- whois.nic.io
- RDAP server
- none reported to IANA
- At 1blu
- on request via kissdomain
Registration conditions
- Who may register?
- Under .io anyone, regardless of residence. Third-level names only for residents of the British Indian Ocean Territory.
- Length
- At most 63 characters per label; names must conform to the DNS standards (RFC 1034, 1035, 1122, 1123). Certain one- or two-letter names and number names are only allocated in a separate controlled process.
- Characters
- a–z, 0–9 and hyphen as per the DNS standards. No hyphen at the beginning or end.
- Technology
- At least two working name servers; their location does not matter.
- Use
- No use for sexual or pornographic content or contrary to applicable law. The registry's spam rules apply.
- Registrant data
- Correct, verifiable contact details.
- Allocation
- In order of application (first come, first served).
- Transfer
- Transfer under the registry's current procedure, directly or via an agent. NIC.IO may charge a fee for it.
The registry's current rules are binding: www.nic.io.
Sources: NIC.IO: Rules · NIC.IO: Terms and conditions · IANA Root Zone Database: .io · As of 28 October 2026