Integrating Crypto Payments Using Libraries

Unstoppable Domains provides a set of resolution libraries for ease of integrating crypto payments into your applications. They directly communicate with the Ethereum, Polygon, and Zilliqa blockchains to retrieve domain records, so you do not have to. Please see the Resolution Libraries Overview for a detailed description and configuration.

Resolving a Crypto Address From a Domain

To resolve a domain into an address, you must call the appropriate method from the resolution library in the language you choose and pass the required parameters (currency and domain).

JavaScriptJavaSwiftGolang

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const {default: Resolution} = require('@unstoppabledomains/resolution');
const resolution = new Resolution();
resolution
  .addr('ryan.crypto', 'ETH')
  .then((receiverETHAddress) => {
    // receiverETHAddress consists receiver ethereum address
    // use this address as recipient of the payment
  })
  .catch(console.error);

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import com.unstoppabledomains.resolution.Resolution;

DomainResolution resolution = new Resolution();
String receiverETHAddress = resolution.getAddress("ryan.crypto", "ETH");
// receiverETHAddress consists receiver ethereum address
// use this address as recipient of the payment

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import UnstoppableDomainsResolution

guard let resolution = try? Resolution() else {
  print ("Init of Resolution instance with default parameters failed...")
  return
}

resolution.addr(domain: "ryan.crypto", ticker: "ETH") { result in
  switch result {
  case .success(let returnValue):
    let receiverETHAddress = returnValue
    // receiverETHAddress consists receiver ethereum address
    // use this address as recipient of the payment
  case .failure(let error):
    print("Expected eth Address, but got \(error)")
  }
}

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package main

import (
    "fmt"
    "github.com/unstoppabledomains/resolution-go"
)

func main() {
    uns, _ := resolution.NewUnsBuilder().Build()
    ethAddress, _ := uns.Addr("ryan.crypto", "ETH")
    fmt.Println("ETH address for ryan.crypto is", ethAddress)
}

We resolved the ryan.crypto domain into its records and retrieved the Ethereum address using the Resolution Library in the code snippet above.

Records Involved

In the code above, the addr() and getAddress() methods convert the provided 3-letter ticker into the format crypto.<TICKER>.address and queries the blockchain for the attached record. Some applications also set custom records for a domain to use within themselves.

Resolving Addresses Existing on Multiple Blockchains

The resolution library provides another method for resolving the addresses of tickers for different blockchains (e.g. USDT exists on EOS, ERC20, OMNI, and TRON blockchains). The code snippet below shows how to handle this for the udtestdev-usdt.crypto domain:

JavaScriptJavaSwiftGolang

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const {default: Resolution} = require('@unstoppabledomains/resolution');
const resolution = new Resolution();
resolution
    .multiChainAddr('udtestdev-usdt.crypto', 'USDT', 'ERC20')
    .then((receiverUSDTAddress) => {
        // receiverUSDTAddress consists address for receiving USDT on Ethereum (ERC20 version)
        // use this address as recipient of the payment
    })
    .catch(console.error);

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import com.unstoppabledomains.resolution.Resolution;

DomainResolution resolution = new Resolution();
String receiverUSDTAddress = resolution.getMultiChainAddress("udtestdev-usdt.crypto", "USDT", "ERC20");
// receiverUSDTAddress consists address for receiving USDT on Ethereum (ERC20 version)
// use this address as recipient of the payment

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import UnstoppableDomainsResolution

guard let resolution = try? Resolution() else {
  print ("Init of Resolution instance with default parameters failed...")
  return
}

resolution.multiChainAddress(domain: "udtestdev-usdt.crypto", ticker: "USDT", chain: "ERC20") { (result) in
  switch result {
  case .success(let returnValue):
     receiverUSDTAddress = returnValue;
     // receiverUSDTAddress consists address for receiving USDT on Ethereum (ERC20 version)
     // use this address as recipient of the payment
  case .failure(let error):
     print("Expected USDT-ETC20 Address, but got \(error)")
  }

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package main

import (
    "fmt"
    "github.com/unstoppabledomains/resolution-go"
)

func main() {
    uns, _ := resolution.NewUnsBuilder().Build()
    usdtAddress, _ := uns.AddrVersion("udtestdev-usdt.crypto", "USDT", "ERC20")
    fmt.Println("USDT-ERC20 address for udtestdev-usdt.crypto is", usdtAddress)
}

Records Involved

The multiChainAddr(), multiChainAddress(), getMultiChainAddress(), and AddrVersion() methods create a key from the provided USDT ticker and ERC20 version. The key format is crypto.USDT.version.<VERSION>.address. In the example above with the ERC-20 version of USDT, the created key would be crypto.USDT.version.ERC20.address.

info

Please see the Managing Domain Records guide for information about supported crypto payment tickers and USDT versions.

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