The .io domain has considerable usage unrelated to the British Indian Ocean Territory. In computer science, “IO” or “I/O” is commonly used as an abbreviation for input/output, which makes the .io domain desirable for services that want to be associated with technology. .io domains are often used for open source projects, application programming interfaces (“APIs”), startup companies, video games, and other online services.
Here is the current status of 26 single letter dot io domain names:
A.io: has specialized in the acquisition and brokerage of premium domain names, websites and Internet based businesses since June, 1997 and joined Tucows in January, 2000 as one of their first Registration Partners utilizing the OpenSRS platform.
B.io: is a new and unique platform where your biography is hosted, updated, translated
C.io: Is available for sale
D.io: Developed a website that says “We’re on a mission to make organizing events simpler and more productive with a beautiful and functional design.
E.io: Is available for sale
F.io: Unresolved page
G.io: Looks like parked and maybe for sale
H.io: Is available for sale
I.io: Is available for sale
J.io: Is available for sale
K.io: Purveyors of the finest internet solutions since 2002. Krystal is an internet services company specialising in a range of tools, solutions & services for businesses all over the world. From web hosting and cloud services to voice over IP and customer support platforms
L.io: Is available for sale
M.io: Chat in one place,not all over the place. Connect with the people you work with on Slack, Microsoft Teams, and Cisco Webex.
N.io: forwards to NioLabs.com – niolabs simplifies IoT development from edge to cloud use the nio software platform to rapidly design, deploy, and monitor distributed IoT applications.
O.io: Unresolved page
P.io: Is available for sale
Q.io: Is available for sale
R.io: Unresolved page
S.io: Forwards to SIO.com For more than 15 years we have been dealing with software architecture and development, as well as the design of online marketing campaigns and have already successfully completed numerous projects for innovative medium-sized and large companies.
T.io: Forwards to Tenable.com – Today, over 30,000 organizations around the world rely on us to help them understand and reduce cybersecurity risk. Our goal is to arm every organization, no matter how large or small, with the visibility and insight to answer four critical questions at all times: Where are we exposed? Where should we prioritize based on risk? Are we reducing our exposure over time? How do we compare to our peers?
U.io: Is available for sale
V.io: Forwards to Vanadium.com – Creates mobile and distributed applications that work even without an Internet connection.
W.io: Is available for sale
X.io: Forwards to Otoy.com website – OTOY Inc. is the definitive cloud graphics company, pioneering technology that is redefining content creation and delivery for media and entertainment organizations around the world.
Y.io: Is available for sale
Z.io: Is available for sale.
These domains looks like available for sale, though some domains resulted in an unresolved page:
C.io, E.io, f.io, g.io, h.io, i.io, j.io, l.io, o.io, p.io, q.io, r.io, u.io, w.io, y.io, and z.io
Other domains forwards to someother website or are in a developed mode of operation. It is intersting to note that some three letter .com domain like sio.com is also owning s.io as a more shorter url. Most developed websites are being in used in tech field.