ENS integration in an application encompasses several critical features, each of which can be implemented independently. While comprehensive ENS integration is ideal, even basic support can be a huge benefit to users. Below, we outline three levels of ENS integration. Level 1 is easily achieved and provides high impact for users, while levels 2 and 3 provide more functionality to your users, improving your DApp's usability and your users' experience interacting with your DApp.
The first step to supporting ENS in your application is making your application understand ENS names, and accepting them anywhere an address is accepted. To understand how to do this, see Resolving Names.
If possible, when a user enters an ENS name instead of an address, remember the ENS name, not the address it currently resolves to. This makes it possible for users to update their ENS names and have applications they used the name in automatically resolve to the new address, in the same way that you would expect your browser to automatically direct you to the new IP address if a site you use changes servers.
If your application deals with user funds or other critical resources, you may want to keep track of the address a name resolves to and warn them when it changes, to ensure they are aware of the change.
By accepting ENS names in your application, you remove the need for users to copy and paste - or worse, type out - long and opaque Ethereum addresses, which leads to errors and lost funds.
The second level of ENS integration involves displaying ENS names wherever your app currently displays addresses.
If a user entered an ENS in your DApp, you should retain this name and show it to them whenever you would normally show the address.
If a user entered an address, or the address was obtained from elsewhere, you may still be able to show an ENS name, by doing Reverse Resolution. This permits you to find the canonical name for an address and display that when possible. If no canonical name is provided, your application can fall back to displaying the address as it did previously.
By supporting reverse resolution, you make it easier for your users to identify accounts they interact with, associating them with a short human-readable name instead of a long opaque Ethereum address.
The final step for comprehensive ENS integration is to facilitate associating ENS names with resources created by or managed with your application. This can take two forms:
By obtaining an ENS name for your product and allowing users to easily register subdomains, you can provide users with an easy way to name resources created in your DApp. For example, if your DApp is a cryptocurrency wallet, you can make it easy for users to obtain an ENS domain of the form theirname.yourwallet.eth, allowing them to give their name out to others more easily.
To learn how to do this, see Writing a Registrar in the Smart Contract Developer Guide.
By providing users with an easy way to update a name they own to point at your application’s resources, users can assign names they already own to your DApp's resources. See Managing Names to learn how to do this.