Alchemy Error: what is the meaning of this -> maxFeePerGas cannot be less than maxPriorityFeePerGas

Question

I am following this tutorial -> https://docs.alchemy.com/alchemy/tutorials/sending-txs The only difference is that i am trying to eth to ropsten test faucet

async function main() {
  require('dotenv').config();
  const { API_URL, PRIVATE_KEY } = process.env;
  const { createAlchemyWeb3 } = require('@alch/alchemy-web3');
  const web3 = createAlchemyWeb3(API_URL);
  const myAddress = 'xxxx'; //TODO: replace this address with your own public address

  const nonce = await web3.eth.getTransactionCount(myAddress, 'latest'); // nonce starts counting from 0
  console.log(nonce);
  const transaction = {
    to: '0x9f1099b301716892d17d576387027cE5B73E2c20', // faucet address to return eth
    value: 100,
    gas: 30000,
    maxFeePerGas: 1000000108,
    nonce: nonce,
    // optional data field to send message or execute smart contract
  };

  const signedTx = await web3.eth.accounts.signTransaction(
    transaction,
    PRIVATE_KEY
  );

  web3.eth.sendSignedTransaction(
    signedTx.rawTransaction,
    function (error, hash) {
      if (!error) {
        console.log(
          '🎉 The hash of your transaction is: ',
          hash,
          "\n Check Alchemy's Mempool to view the status of your transaction!"
        );
      } else {
        console.log(
          '❗Something went wrong while submitting your transaction:',
          error
        );
      }
    }
  );
}

main();

When i am running code i am getting this error -> Error: maxFeePerGas cannot be less than maxPriorityFeePerGas (The total must be the larger of the two) (tx type=2 hash=not available (unsigned) nonce=23 value=100 signed=false hf=london maxFeePerGas=1000000108 maxPriorityFeePerGas=2500000000)

Update : if i replace maxFeePerGas with maxPriorityFeePerGas this works

What am i missing conceptually?

Answer 1

It seems that the default value of maxPriorityFeePerGas was changed from 1.0 gwei to 2.5 gwei due to some incentive mechanism for miners.

Follow this issue for more detailed information.

Hence, if we don't set the maxPriorityFeePerGas parameter, the default value 2.5 gwei would larger than maxFeePerGas, which is 1.0 gwei we set and violate the rule.

We can solve this issue by either setting maxPriorityFeePerGas smaller than 1.0 gwei or changing maxFeePerGas larger than 2.5 gwei.