Why Do IO Games use the .IO Extension?


I don’t know about you, but the last time I wanted to register a new domain, it took me a while to find one that suited my needs and was easy to remember. In the end, I had to settle for a .net extension. All the .com descriptive dictionary domains are long gone, .net and .co are closely following suit. However, there is a little ray of sunshine, .io extensions.

What Are .io TLDs?

Quite simply the .io extension is the top level domain for British Indian Ocean Territory. The country code for which is, io. The very first .io to be registered was levi.io, in 1998.

Why Are .io Domains Useful?

When the .io TLD hit the virtual shelves a few years ago, a whole new world opened up. Not only does the reference to input/output perfectly fit web products are services, but the extension’s late arrival into the market meant it was now possible to acquire a descriptive short-tailed domain name, that perfectly matched your needs. You can even buy two letter domains and chances are you won’t have to start dropping vowels in a desperate attempt to own a domain that matches your product name. And the price point of $95 for registration and $30 per subsequent years, helped to keep the number of registered domains pretty low.

With the freely open availability of desired domain names and inherent links to the tech/web industry, it should not be a surprise to anyone that techies startups and web services started to spring up, all with .io TLDs. Of course, other people/developers building a web based product started to use these domains too.

Use of the .io TLD in Games.

When Agar.io was first created, it didn’t have a name. A 4chan user suggested the name Agar.io as other domain names that would have matched the game were already taken.

You probably know that Agar.io was a massive success. In the early days, users were constantly streaming on Twitch and producing new videos on Youtube. This social propagation saw Agar.io rise into the 1000 most visited websites, as documented by Alexa. This caught the attention of other game developers. I mean, what game developer wouldn’t be inspired by seeing a very simple game rise out of obscurity and take the world by storm? In all honesty, Agar.io was the reason I started to learn Node.js.

On March 25, 2016, Slither.io was released. The developer, Steve Howse, took the basic nature of Agar.io and gave it a little sparkle. He gave his game more aesthetically pleasing graphics, additional game mechanics and a touch of nostalgia. In the months that followed Slither.io dwarfed Agar.io in popularity. It quickly secured a top spot in the app stores and held on for quite some time.

With its meteoric rise to stardom, Slither.io set the standard for easily consumable web-based games.  The games fame did not pass the attention indie game developers.  The developers of new games wanted to share in the popularity and buzz that was still surrounding Slither.io and so they latched onto the use of the .io web extension. Games using the .io extension starting to spring up on a weekly basis. With them came the need for a system to catalogue these new games.

Gaming portals like Miniclip started to catalogue the new games under a category dubbed “.io games” and thus the genre had a name. And as with every gaming category, a marketplace starts to develop and as sites like this are created to share .io games with users.


Everything boils down to availability and following trends. Games like Agar.io and Slither.io chose to use .io domains because they could buy a domain they liked, without having to compromise on vowels. Later games followed the path laid out by their predecessors.

So, if you want to make a game in the shadow of Slither.io or even Diep.io, chances are you will want to buy a .io domain name. You had better be quick. Even though they are expensive, they are being bought up very quickly and soon, the domain name you want will be gone.