How to Send ERC-20 Tokens Using the Kaia SDK (USDT Example)

Overview

In this guide, you will learn how to programmatically send ERC 20 tokens using USDT as an example on the Kaia blockchain with the ethers-ext SDK. The Kaia SDK is a collection of libraries including ethers-ext, web3js-ext, viem-ext, web3j-ext, and web3py-ext that help developers interact with Kaia nodes across different programming environments.

This guide focuses on using the ethers-ext SDK to send USDT tokens through a smart contract call.

Prerequisite

A MetaMask Account (a dev account was used for this example)
Obtain test KAIA from the Faucet

Step 1: Setup project and install ethers-ext and ethers.js


mkdir send-usdt-kaiasdk
cd  send-usdt-kaiasdk
npm init -y  
npm install --save @kaiachain/ethers-ext ethers@6 dotenv

Step 2: Set up Provider and Wallet instance

Create a new file named index.js and paste the code below into it.


import { ethers } from "ethers";
import { Wallet, JsonRpcProvider, parseKaiaUnits } from "@kaiachain/ethers-ext/v6";
import "dotenv/config";
const senderPriv = process.env.USDT_SENDER;
const recipientAddress = "PASTE_RECIPIENT_ADDRESS"
const amount = parseKaiaUnits("0.01", 6);
const provider = new JsonRpcProvider("https://public-en.node.kaia.io");
const wallet = new Wallet(senderPriv, provider);

Step 3: Create USDT contract instance


const USDT_CONTRACT_ABI = [
{
    "inputs": [
      {
        "internalType": "address",
        "name": "recipient",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "amount",
        "type": "uint256"
      }
    ],
    "name": "transfer",
    "outputs": [
      {
        "internalType": "bool",
        "name": "",
        "type": "bool"
      }
    ],
    "stateMutability": "nonpayable",
    "type": "function"
},
{
    "inputs": [
      {
        "internalType": "address",
        "name": "account",
        "type": "address"
      }
    ],
    "name": "balanceOf",
    "outputs": [
      {
        "internalType": "uint256",
        "name": "",
        "type": "uint256"
      }
    ],
    "stateMutability": "view",
    "type": "function"
}
]
const USDT_CONTRACT_ADDRESS = "0xd077a400968890eacc75cdc901f0356c943e4fdb";
async function main() {
  const USDT_CONTRACT = new ethers.Contract(USDT_CONTRACT_ADDRESS, USDT_CONTRACT_ABI, wallet);
}

Step 4: Send Tokens


async function main() {
  const USDT_CONTRACT = new ethers.Contract(USDT_CONTRACT_ADDRESS, USDT_CONTRACT_ABI, wallet);
  console.log("balance of recipient before", (await USDT_CONTRACT.balanceOf(recipientAddress)).toString());
  const sentTx = await USDT_CONTRACT.transfer(recipientAddress, amount);
  const receipt = await sentTx.wait();
  console.log("receipt", receipt.hash);
  console.log("balance of recipient after", (await USDT_CONTRACT.balanceOf(recipientAddress)).toString());
}
main();

Full Code


import { ethers } from "ethers";
import { Wallet, JsonRpcProvider, parseKaiaUnits } from "@kaiachain/ethers-ext/v6";
import "dotenv/config";
const senderPriv = process.env.USDT_SENDER;
const recipientAddress = "PASTE RECIPIENT ADDRESS"
const amount = parseKaiaUnits("0.01", 6);
const provider = new JsonRpcProvider("https://public-en.node.kaia.io");
const wallet = new Wallet(senderPriv, provider);
/* 
Get USDT ABI here: https://kaiascan.io/address/0xd077a400968890eacc75cdc901f0356c943e4fdb?tabId=contract&page=1
*/
const USDT_CONTRACT_ABI = [
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "recipient",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "amount",
        "type": "uint256"
      }
    ],
    "name": "transfer",
    "outputs": [
      {
        "internalType": "bool",
        "name": "",
        "type": "bool"
      }
    ],
    "stateMutability": "nonpayable",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "account",
        "type": "address"
      }
    ],
    "name": "balanceOf",
    "outputs": [
      {
        "internalType": "uint256",
        "name": "",
        "type": "uint256"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  }
]
const USDT_CONTRACT_ADDRESS = "0xd077a400968890eacc75cdc901f0356c943e4fdb";
async function main() {
  const USDT_CONTRACT = new ethers.Contract(USDT_CONTRACT_ADDRESS, USDT_CONTRACT_ABI, wallet);
  console.log("balance of recipient before", (await USDT_CONTRACT.balanceOf(recipientAddress)).toString());
  const sentTx = await USDT_CONTRACT.transfer(recipientAddress, amount);
  const receipt = await sentTx.wait();
  console.log("receipt", receipt.hash);
  
  console.log("balance of recipient after", (await USDT_CONTRACT.balanceOf(recipientAddress)).toString());
}
main();

Run node index.js in your terminal to see your transaction executed.

Overview​

Prerequisite​

Step 1: Setup project and install ethers-ext and ethers.js​

Step 2: Set up Provider and Wallet instance​

Step 3: Create USDT contract instance​

Step 4: Send Tokens​