What are ENS subdomains?

If you’ve explored web3 for long enough, you’ve likely encountered Ethereum Name Service (ENS) subdomains. ENS subdomains are created by adding a new name to an existing ENS domain name. Let's examine the domain pooltogether.eth. Pooltogether.eth has two parts (or levels): the first is .eth and the second is pooltogether. If we add a third level, the name becomes a subdomain, for example, tim.pooltogether.eth.
Subdomains have garnered a lot of attention, particularly around their potential for long-term utility. Let’s break down what makes subdomains so special, including the different types and why both individuals and companies should take advantage of them.

Types of Subdomains

There are two major categories of subdomains: ones that cost gas and ones that don’t.
Subdomains that cost gas exist on-chain. Creating and editing each subdomain will require a gas fee because they are stored on the blockchain. However, it’s important to note they have no on-going renewal fee. Renewal fees impact the owner of the level two domain only.
Gasless subdomains do not exist on-chain (unless someone sponsors that transaction). A person with a domain could create unlimited gasless subdomains, edit them as often as desired, and never see a single gas fee. They inherently have no on-going renewal fee because their data is stored off-chain.

Benefits of Subdomains

Subdomains have their own unique benefits, making them attractive to individuals and companies alike.
Unlimited names: Domains like nfty.eth can create an unlimited amount of subdomains. Subdomains can then be assigned to family, friends, team members, or even an entire community. This opens up opportunities for branding and work spaces.
Cost efficient: Creating multiple subdomains from a single domain costs significantly less than registering and renewing multiple domains. If using gasless subdomains, the only cost for maintaining these names becomes the cost to manage the second-level domain they originate from. Though it is possible to charge a renewal fee for subdomains via the Name Wrapper and Unruggable Protocol.
Set subdomains as primary: Any subdomain can be set as a primary name. A primary name acts as your display name when connecting to web3 websites and apps. Setting your name as primary will cost a gas fee, no matter the type of subdomain. You can set any subdomain as primary here.
ENS integrations: Subdomains will work wherever ENS is integrated. Since ENS has the most integrations among any domain naming service, these subdomains will resolve in popular dapps like Metamask, Rainbow, Etherscan, Mailchain and more.
For information on how companies can use gasless subdomains, check out our other post.

More on Gasless Subdomains

Gasless subnames are possible thanks to the CCIP-read standard (ERC-3668) and ENS wildcard resolution (ENSIP-10). With CCIP-read, data can be pulled from offchain sources like cloud servers to bypass gas fees. Companies like Coinbase have used this technology to issue over 2 million subdomains to their users. If your company or community is interested in issuing their own branded subnames, NameStone can get you started today.

Want to learn more?

NameStone is founded by Alex Slobodnik, who’s been working with ENS DAO since its beginning. Reach out to Alex on Twitter or Telegram to learn more about NameStone's powerful API and start issuing gasless subdomains today.