error: replacement transaction underpriced

Question

Im trying to send a raw transaction using web3 to ropsten testnet and Im getting this error:

replacement transaction underpriced

where sometimes my tx works and sometimes I get this error.

my tx parameters:

const nonce = web3.eth.getTransactionCount(ethereumConfig.contract.account)
const block = web3.eth.getBlock("latest")
const gasLimit = block.gasLimit
const gasPrice = web3.eth.gasPrice.toNumber() * 1.40 

note I'm already adding 40% to gasPrice

Answer 1

I have been running into this issue as well. The network thinks you are trying to replace an existing unmined transaction. There are two ways to avoid this:

1. Adding a gas price %10 higher than the existing unmined transaction's gas price.
2. Increase your nonce to one higher than the unmined transaction.

I have also been getting this error:

"Transaction was not mined within 50 blocks, please make sure your transaction was properly send. Be aware that it might still be mined!"

In my case, I think the transaction is getting stuck in limbo somehow. It's not being mined by anyone, but it's not being removed from the pool of unmined transactions. Keep in mind that web3.eth.getTransactionCount(walletAddress) will only give you the last CONFIRMED nonce. So it won't take the unmined ones into account.

Answer 2

Define the Goal

Do you want to:

1. Send a new transaction, after all your previous transactions have completed, or...
2. Replace a pending (unmined) transaction, with the new raw transaction.

Send a New Transaction

The error message implies that you're trying to replace a pending transaction. That's because the raw transaction you're trying to send has the same nonce as another transaction that you have pending.

Since replacing a transaction is not your goal, simply increase the nonce to be one higher than your last pending transaction. You may need to track this internally, rather than relying on web3.eth.getTransactionCount().

Replace a Pending Transaction

The 10% Minumum

Since your goal is to replace a transaction that is pending, you must try to convince the miners to use your new transaction. To do that, you must use a gas price that is 10% higher* than the gasPrice of the pending transaction.

const gasPrice = web3.eth.gasPrice.toNumber() * 1.40 

note I'm already adding 40% to gasPrice

The quoted code adds 40% to web3.eth.gasPrice. This may not be 10% higher than the pending transaction's gas price. web3.eth.gasPrice may vary over time, and/or you might have set any arbitrary gas price on the pending transaction.

* 10% isn't defined in the protocol, it's just how most nodes & miners implement it.

Determining the Minimum

If you have the hash of the pending transaction, you can determine the required gas price with something like:

replacement_price = web3.eth.getTransaction(pending_txn_hash).gasPrice * 1.101

Note that this is floating point math, which will have rounding errors, so I threw in an extra 10th of a percent to be sure it was over the minimum.

Answer 3

I have seen this when calling the same contract method twice from JavaScript without waiting for the first call to finish by either await or calling a second time in the success callback.

My guess is that contract methods in web3js are not thread safe.

Answer 4

I'm using Ganache and MetaMask suddenly stopped handling transactions, it queued the first one and every subsequent call would return either nothing or "transaction underpriced". Here's how to solve it:

1. In MetaMask, navigate to Settings/Advanced and click on Reset Account.
2. Restart your browser.

If that doesn't help, try reinstalling MetaMask.

Answer 5

Double check your Gas price. Even I am also setup Gas Price but somehow did applied proper Gas Price as well. One of example below screen shot.