Polygon transactions are stuck/transaction underpriced error

Ethers Version

5.6.1

Search Terms

polygon maxPriorityFeePerGas maxFeePerGas

Describe the Problem

There is a harcoded (1.5 gwei) maxPriorityFeePerGas (and maxFeePerGas) in index.ts.

This value is used in populateTransaction.

In case of Polygon, this will either result in a transaction stuck in the mempool, or in case og e.g an Alchemy endpoint, “transaction underpriced” error.

Code Snippet

signer.populateTransaction(txParams)
signer.sendTransaction(txParams)

Where txParams don't contain maxPriorityFeePerGas/maxFeePerGas, and is a type 2 transaction.
(Legacy transactions pass as they use gasPrice only)

Contract ABI

No response

Errors

processing response error (body="{\"jsonrpc\":\"2.0\",\"error\":{\"code\":-32000,\"message\":\"transaction underpriced\"},\"id\":64}", error={"code":-32000}, requestBody="{\"method\":\"eth_sendRawTransaction\",\"params\":[\"0x02f873818981c98459682f0084596898e882520894c54c244200d657650087455869f1ad168537d3b387038d7ea4c6800080c080a07cb6e05c60a2cb7ffc83349bc52ade79afaf9fdb911c64d57aed421caa1ecbcfa05f30023a4d21dd2eab6ea619c8dbb4820ce40c71841baacf8e82cbde7e87602a\"],\"id\":64,\"jsonrpc\":\"2.0\"}", requestMethod="POST",

Environment

No response

Environment (Other)

No response

[robertu7]

My current workaround:

// get max fees from gas station
let maxFeePerGas = ethers.BigNumber.from(40000000000) // fallback to 40 gwei
let maxPriorityFeePerGas = ethers.BigNumber.from(40000000000) // fallback to 40 gwei
try {
    const { data } = await axios({
        method: 'get',
        url: isProd
        ? 'https://gasstation-mainnet.matic.network/v2'
        : 'https://gasstation-mumbai.matic.today/v2',
    })
    maxFeePerGas = ethers.utils.parseUnits(
        Math.ceil(data.fast.maxFee) + '',
        'gwei'
    )
    maxPriorityFeePerGas = ethers.utils.parseUnits(
        Math.ceil(data.fast.maxPriorityFee) + '',
        'gwei'
    )
} catch {
    // ignore
}

// send tx with custom gas
const tx = await contract.multicall(calldata, {
    maxFeePerGas,
    maxPriorityFeePerGas,
})

[Benjythebee]

And my current workaround:

  const feeData = await maticProvider.getFeeData()

  // Start transaction: populate the transaction
  let populatedTransaction
  try {
    populatedTransaction = await contract.populateTransaction.mint(wallet, arg, { gasPrice: feeData.gasPrice })
  } catch (e) {
    return
  }

I removed gasLimit from the options as it never worked;