Listen to ethereum transactions on a specific address

Question

Is it possible to listen to transactions on a specific ethereum address? For example, if someone sends a certain amount of ETH to that address, the callback function would be triggered.

I read this: How to explore all transactions for a given account? but it seems to be about past transactions and not listening live.

Answer 1

You can use Web3.js 1.0 and WebSockets to accomplish this.

var subscription = web3.eth.subscribe('logs', {
address: '0x123456..',
}, function(error, result){
if (!error)
console.log(result);
})
.on("data", function(log){
console.log(log);
})
.on("changed", function(log){
});

If you use the above code, simply update the address property.

Working sample here: https://jsfiddle.net/h7nskoyu/11/

This looks at the CryptoKitties contract, and when looking at the console you see this:

The expanded transaction maps to this: https://etherscan.io/tx/0x3ccce0b8072649ca087a91f00bdbb475b36d03a9a8dd2cc54b9a03ac5826c255

Learn more about web3.eth.subscribe here.

Answer 2

It's called Continuous monitoring concept. You can also do it using RPC Call. Using Etherscan API (There are many platform which provides ETH API)

Step 1 : Get Latest Block Height using https://api.etherscan.io/api?module=proxy&action=eth_blockNumber&apikey=YourApiKeyToken

Step 2 : Get all details of that block using https://api.etherscan.io/api?module=proxy&action=eth_getBlockByNumber&tag=0x5A0F60&boolean=true&apikey=YourApiKeyToken (You will get all transaction under this block)

Step 3 : Now store all that transaction's data from json to your list and run for loop for your address which you want to monitor continuous.

So now if your address will be in that block's transaction list then you can use details as per your requirement else you can check next generated block after 10 to 15 seconds (as per your requirement).

Answer 3

The accepted answer will only work for txn to a contract.

For detecting ether transfers ( txn to EOAs ) you'll have to setup a listener for getting latest blocks & query on the transactions array of the block to find a match for a particular requirement.

Answer 4

This will monitor the blockchain for incoming transaction for an address

const monitorTransaction = async (addressss)=>{
    
        const block = await web3.eth.getBlock('latest');
    
        console.log(`Checking new block ${block.number}`)
    
        for(let txHash of block.transactions){
            // console.log(txHash);
            const tx = await web3.eth.getTransaction(txHash)
            // console.log(JSON.stringify(tx));
            const tranx = typeof tx === 'string' ? tx.to.toLowerCase() : '';
    
                if(addressss === tranx){
                    console.log(`New transaction found - Block ${block.number}`);
                    console.log(`Transaction From: ${tx.from}`);
                    console.log(`Transaction To: ${tx.to}`);
                    console.log(JSON.stringify(tx));
                }
        }
    }