Primary Names

We can all agree 42-character long machine-optimized addresses (eg. 0x225...c3b5) are not aesthetically pleasing. Fortunately, it is super easy to retrieve a user's preferred name, and this page will show you how.

0x225...c3B5to

luc.eth

In order to convert them to human-readable names, we use the reverse registrar. The reverse registrar is a smart contract that allows users to register their preferred name, referred to as their "primary name" for simplicity purposes.

Getting a Primary Name

To get a users preferred primary name is very simple. In most libraries you will find a function to do a lookup by address as shown below. This allows us to turn any address into a human-readable name.

Reverse Lookup

WagmiEthers.js v5ViemGo

import { useEnsName } from 'wagmi';

export const Name = () => {
    const { data: name } = useEnsName({
        address: '0x225f137127d9067788314bc7fcc1f36746a3c3B5',
    });

    return <div>Name: {name}</div>;
};

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Try it out

// 0x225f137127d9067788314bc7fcc1f36746a3c3B5 -> luc.eth
const name = await provider.lookupAddress(
    '0x225f137127d9067788314bc7fcc1f36746a3c3B5'
);

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// 0x225f137127d9067788314bc7fcc1f36746a3c3B5 -> luc.eth
import { publicClient } from './client';

const ensName = await publicClient.getEnsName({
    address: '0x225f137127d9067788314bc7fcc1f36746a3c3B5',
});

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Try it out

package main

import (
	"fmt"

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/ethclient"
	ens "github.com/wealdtech/go-ens/v3"
)

func main() {
	client, _ := ethclient.Dial("https://rpc.ankr.com/eth")

	name, _ := ens.ReverseResolve(client, common.HexToAddress("0x225f137127d9067788314bc7fcc1f36746a3c3B5"))
	fmt.Println("Name:", name)
	// Name: luc.eth
}

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🎉 And that's it! Now you can turn all your pages from this, to this:

Setting Primary Names

In some cases you might want to encourage users to set their primary name. This might be in the event you are issuing names, or want people to be part of a community. Most users are expected to do this through the ENS Manager, however it is totally doable from 3rd-party platforms as well.

// TODO: Write Code Snippet

import { createWalletClient, custom } from 'viem';
import { mainnet } from 'viem/chains';

import { addEnsContracts } from '@ensdomains/ensjs';
import { setPrimaryName } from '@ensdomains/ensjs/wallet';

const wallet = createWalletClient({
    chain: addEnsContracts(mainnet),
    transport: custom(window.ethereum),
});

const hash = await setPrimaryName(wallet, {
    name: 'ens.eth',
});
// 0x...

Do's and Dont's

It must be noted that under no situation is it recommended to force a user to change their primary name, nor doing so without clearly notifying the user of what the transaction they are about to execute could modify. Doing so could be seen as hostile or undesired behaviour by end users and might degrade their experience with your app.