Forward Resolution: Convert ENS names (e.g., vitalik.eth) to Ethereum addresses
Reverse Resolution: Convert Ethereum addresses to ENS names
Chain Detection: Automatically detects and displays the connected chain
Error Handling: Comprehensive error messages for common issues
Timeout Control: Configurable timeout for operations

Prerequisites

Go 1.23.0 or later
Access to an Ethereum RPC endpoint (Mainnet or Sepolia)
- Get one from Infura or Alchemy
- Or run your own Ethereum node

Build

cd examples/ens-resolver-example
go build

This will create an executable named ens-resolver-example (or ens-resolver-example.exe on Windows).

Run

Basic Usage

Forward Resolution (ENS name → address):

./ens-resolver-example -rpc https://mainnet.infura.io/v3/YOUR-PROJECT-ID -name vitalik.eth

Reverse Resolution (address → ENS name):

./ens-resolver-example -rpc https://mainnet.infura.io/v3/YOUR-PROJECT-ID -address 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045

Command-Line Flags

Flag	Description	Required	Default
`-rpc`	Ethereum RPC endpoint URL	Yes	-
`-name`	ENS name for forward resolution	No*	-
`-address`	Ethereum address for reverse resolution	No*	-
`-timeout`	Operation timeout duration	No	30s
`-help`	Show help message	No	false

*Note: Either -name or -address must be provided, but not both.

Examples

Forward Resolution

Resolve an ENS name to an Ethereum address:

./ens-resolver-example -rpc https://mainnet.infura.io/v3/YOUR-PROJECT-ID -name vitalik.eth

Output:

Connecting to RPC endpoint: https://mainnet.infura.io/v3/YOUR-PROJECT-ID
Connected to Ethereum Mainnet (Chain ID: 1)

Resolving ENS name: vitalik.eth
----------------------------------------
✓ Successfully resolved
  ENS Name: vitalik.eth
  Address:  0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045

Reverse Resolution

Resolve an Ethereum address to an ENS name:

./ens-resolver-example -rpc https://mainnet.infura.io/v3/YOUR-PROJECT-ID -address 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045

Output:

Connecting to RPC endpoint: https://mainnet.infura.io/v3/YOUR-PROJECT-ID
Connected to Ethereum Mainnet (Chain ID: 1)

Performing reverse resolution for: 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045
----------------------------------------
✓ Successfully resolved
  Address:  0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045
  ENS Name: vitalik.eth

Using Sepolia Testnet

./ens-resolver-example -rpc https://sepolia.infura.io/v3/YOUR-PROJECT-ID -name test.eth

Custom Timeout

Set a custom timeout for slow networks:

./ens-resolver-example -rpc https://mainnet.infura.io/v3/YOUR-PROJECT-ID -name vitalik.eth -timeout 1m

Supported Chains

ENS resolution is only available on:

Ethereum Mainnet (Chain ID: 1)
Sepolia Testnet (Chain ID: 11155111)
Holesky Testnet (Chain ID: 17000)

Attempting to use other chains will result in an error.

Error Handling

The tool provides clear error messages for common issues:

Invalid ENS Name
No Reverse Record
Unsupported Chain
Connection Error