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.io vs .co

Which domain extension should you choose? Here's how the two compare — and when each one is the better pick.

.io The ccTLD of the British Indian Ocean Territory, adopted by startups and developers because "I/O" means input/output. .co Colombia's country code, relaunched worldwide in 2010 as a short alternative to .com.

Side by side

.io.co
What it isBritish Indian Ocean Territory's ccTLDColombia's ccTLD
Runs the registryInternet Computer Bureau LimitedMinistry of Information and Communications Technologies (MinTIC)
In the root zone sinceEarly ccTLD (date not recorded)Early ccTLD (date not recorded)
Popular meaninginput/output — the startup and developer favoritecompany, or a short alternative to .com
Search geotargetingccTLD that Google treats as genericccTLD that Google treats as generic
DNSSEC-signedYesYes
Name servers (IPv6)4 (4)4 (4)

Choose .io if…

  • Developer tools, APIs and SaaS products
  • Short, available names that are long gone on .com
  • Tech audiences who read ".io" as a signal, not a red flag

Watch out for

  • Renewal prices are noticeably higher than .com at most registrars
  • The territory's sovereignty is moving to Mauritius, which raises long-term questions about the ccTLD
  • Non-technical customers may still type .com by habit

Still a solid choice for developer tools and tech brands, but know that it rests on a territory whose status is changing. For a company meant to last decades, also hold the .com.

Everything about .io → Register a .io domain (British Indian Ocean Territory) ↗.io WHOIS lookup ↗Sell .io domains via API ↗

Choose .co if…

  • Startups and small businesses wanting a short brand
  • Companies that read ".co" as "company"
  • Colombian businesses, obviously

Watch out for

  • Visitors and email senders often autocorrect to .com
  • If someone else owns your name on .com, you'll leak traffic and email to them

A good second choice when the .com is gone, especially for short names. Own the .com too if you can, because people will type it.

Everything about .co → Register a .co domain (Colombia) ↗.co WHOIS lookup ↗Sell .co domains via API ↗

Check one name on both endings

Type a name and see whether it's free as .io, .co and other endings.

Atak Domain is our sister registrar.

.io vs .co FAQ

Is .io better than .co?

Neither is better across the board. Still a solid choice for developer tools and tech brands, but know that it rests on a territory whose status is changing. For a company meant to last decades, also hold the .com. A good second choice when the .com is gone, especially for short names. Own the .com too if you can, because people will type it.

Does .io or .co rank better on Google?

Google doesn't give either ending a ranking bonus. What differs is geotargeting: .io is cctld that google treats as generic, and .co is cctld that google treats as generic. Content and links matter far more than the TLD.

Can I use both .io and .co?

Yes, and many brands do: register both, pick one as the main site, and redirect the other to it so links and email never go astray.