how to make batch transaction in ethereum?

Question

Is it possible sending ether to multiple addresses in one go, better called batch sending? I want to make an API to transfer ether to 100 address at once so that I do not need to make 100 transactions.

Answer 1

Here is Dapp to make it easier for you: https://multisender.app

If you want to do it yourself, here is some code for you

contract MultisenderApp {

function multisendEther(address[] calldata _contributors, uint256[] calldata _balances) external payable {
    uint256 total = msg.value;
    uint256 i = 0;
    for (i; i < _contributors.length; i++) {
        require(total >= _balances[i]);
        assert(total - _balances[i] > 0);
        total = total - _balances[i];
        (bool success, ) = _contributors[i].call.value(_balances[i])("");
        require(success, "Transfer failed.");
    }
}    

this way, you can be sure that whoever interacts with this function, won't take more eth than he/she should.

Answer 2

This can be kinda of delicate at times, but web3 does support batch requests https://github.com/ethereum/wiki/wiki/JavaScript-API#batch-requests Here is their example on their site. I can include an example for sending ether if this is not clear

var batch = web3.createBatch();
batch.add(web3.eth.getBalance.request('0x0000000000000000000000000000000000000000', 'latest', callback));
batch.add(web3.eth.Contract(abi).at(address).balance.request(address, callback2));
batch.execute();

The Specific example would be something akin to eth.sendTransaction({from:sender, to:receiver, value: amount})

var batch = web3.createBatch();
batch.add(web3.eth.sendTransaction({from:sender, to:receiver, value: amount}));
batch.add(web3.eth.sendTransaction({from:sender, to:receiver2, value: amount2}));
batch.execute();

Just an FYI Batching requests do not make them faster! Making many requests at once will sometimes be faster, as requests are processed asynchronously. Batch requests are mainly used to ensure events happen in serial.

Answer 3

function sendBatch(address[] _addrs) public payable {
    for(uint i = 0; i < _addrs.length; i++) {
        _addrs[i].transfer(msg.value.div(_addrs.length));
    }
}

This simple solidity function would do exactly what you're asking about. You would just need to provide an array of addresses when executing the function and it will split the ETH you send to all those addresses evenly.

Answer 4

if you want batch send Ether or Token,you can use: https://algocryptodapp.github.io/Bee-Sender/

or send ether use solidity:

 for (uint i=0; i < address.length; i++) {
            address[i].transfer(amounts[i]);
        }
}