List of registered .IO domains

233,758 domains in this list

2,520 domains added on last update

List type Updated Domains in list
.IO zone domain list (standard) November, 2020 233,758
.IO zone domain list (detailed) November, 2020 233,758

Standard domain list includes the list of domain names (plain text format, one domain name per line).

Detailed domain list comes in .CSV (comma-separated) format download sample

It includes some additional fields:

  1. Domain name
  2. DNS servers (if any)
  3. IP (if any)
  4. Country by IP (if any)
  5. Country by HTML codepage (if any)
  6. Web server type (if any)
  7. Hostname (if any)
  8. Emails (if any)
  9. Alexa traffic rank (if any)
  10. Phone numbers (if any)
  11. Majestic traffic rank (if any)
  12. Discovery date

— Why we do not provide daily updates for .io zone?
— Country-code registars never open their zone files to the public. The only way to discover domains in country-code zones is to do a massive recursive scan of all known websites. That's what we're doing. We use a massive cluster of servers and crawl the Web, then we check and clean the resulting lists. We know of millions of CCTLD-domains in hundreds of zones (and currently know of 233,758 domains in .io zone), but we do not cover 100% of them (some of the smaller websites simply do not have any inbound links and that means that our crawlers cannot find them). Meanwhile we regularly add new domains to this list (1 time / month).

.io zone details


Total domains in this zone: 233,758

Unique IPs: 49,078

Active websites: 195,664

Total phones: 5,062

Total emails: 36,890


Last update (UTC time): Nov 29, 2020 08:11


Web Server Usage Statistics

Website Geo Location


.IO zone registar
IO Top Level Domain Registry
Cable and Wireless
Diego Garcia
British Indian Ocean Territory

Zone WHOIS server
whois.nic.io

The .IO domain extension is one of the fastest growing domain extensions in the computer world today. It also happens to be one of the priciest. The name seems to be a reference to 'input/output', a common phrase in the world of technology. This is a top-level domain and its history is both intriguing and shocking.

.IO is the ccTLD (top-level domain) for the British Indian Ocean Territory (BIOT), a network of islands belonging to the British government but used primarily as military bases and lookout posts by the US military. This group of islands, also known as the Chagos Archipelago, was taken by the British in 1965 by separating them from the colony of Mauritius, which soon achieved independence. They have always been considered an area of great strategic importance and the British government has gone to great lengths to keep them in its possession, including having the entire area registered as a Marine Protected Reserve in 2010.

The current registrar of the .io zone is the Internet Computer Bureau and was assigned to it in 1997. The Internet Computer Bureau is a small company operating out of Bournemouth, UK. All .io registrations are ultimately done with the authority of the ICB.

Despite the fact that the .io extension was initially made for the BIOT, the only website actually registered in BIOT with this extension is sure.com, the only network provider in the area. A simple traceroute will show the list of IP addresses leading there. Most of the websites listed with the .io extension happen to be technology startups or blogs of one kind or another. From Bitcoin blogs to SaaS websites, to device manufacturers, .io has become the home for tech.