Smart Contract Event Listener Server


I want to build a simple server that monitors the events of one smart contract and logs them into the terminal.

I have used web3 npm module and programmed the logic of listening to smart contract events and logging them to the console.

When I do “npm start” which does “node server.js”, it immediately returns to the terminal. I was expecting it to hang there and keep logging received events.

How can I make the server keep running and monitoring for emitted events of the smart contract?

Can you share the code from server.js?
How is that you don’t run node server.js directly?


import startRelay from "./relay";




import {
} from "./blockchain";

const start = () => {
    newTransfer((error, result) => {

export default start;



import Web3 from "web3";

const web3 = new Web3(new Web3.providers.HttpProvider(process.env.WEB3_PROVIDER_ADDRESS));
const bep20Abi = JSON.parse(process.env.BEP20_ABI);
const tokenContract = web3.eth.contract(bep20Abi).at(process.env.TOKEN_CONTRACT_ADDRESS);

export const newTransfer = (callback) => {
    tokenContract.Transfer((error, result) => callback(error, result));

How is that there is no startRelay string in relay.js?

In relay.js “start” function is default. I assume that will be called with startRelay() call. Please correct me if I am wrong.

What does this code do?

export const newTransfer = (callback) => {
    tokenContract.Transfer((error, result) => callback(error, result));

I assume it is web3 functionality. It is registering listener to “Tranfer” events emitted from the token contract.

I’m not familiar with this syntax, you can write one single script file and run it and see what errors you get on execution.

How would you do this? A simple server that monitors for the Tranfer events of the token smart contract and logs them.