Alpha Always #5 - Cancelling Stuck Transactions
1/ A relatively short guide for edition #5 of AlphaAlways: we're going to cover how you can cancel a "stuck" transaction.
2/ So, before we start, how do stuck TXs usually happen? Usually, gas spikes.
Gas pushes your transactions through. It's almost like your "bribe" to the miners to take your transaction.
It's got to be high enough for them to want it. If it's not, they won't.
3/ Sometimes, you'll send a transaction at the "going rate" for gas, but suddenly a popular project will start minting, or some degen activity will begin elsewhere in the Metaverse, and suddenly gas spikes.
Your previously attractive gas bid is no longer quite so attractive.
4/ In these cases, you may be left waiting to see whether your transaction will ever confirm.
Etherscan is giving you a confirmation estimate of > 1 hour, and you can't do anything with your wallet.
Woe. 💀
5/ Worse still, if you were going for a popular NFT mint, your transaction may stay pending whilst the collection sells out.
If your transaction then goes through, and all of the NFTs have been minted, your TX may fail and you may still need to pay a hefty TX fee.
❌ 💰 ❌
6/ Can you just wait?
You could do, but depending on network conditions you could be waiting a while and as this is happening, the project you're going for might be minting out, and your chances of a failed TX may be increasing.
7/ So if you want to get back up and running, and make a new transaction, you're likely going to want to cancel your existing transaction.
How do you do that?
8/ MetaMask does have a built in "Cancel" feature, but you'll often find that the gas required to execute that transaction will be pretty damn huge, and can cost $100s.
So how do you get around that? Well we just send ourselves some ETH. Simples. 🥂
9/ How do? Well you could use Metamask for this trick, but my personal experience is that it doesn't seem to work consistently. Your mileage may vary.
As such, I now tend to use our old friend @myetherwallet, which I mentioned in another post.
10/ But before we even start looking to cancel our transaction, we need to understand what we're going to do.
When we send a transaction, that TX has a "nonce". You can think of it as your signal to the Ethereum blockchain, telling it what order your TXs should be sorted in.
11/ Transactions will confirm in sequential order. So if we've already got a pending transaction, it's not enough to simply send another to push it through because it'll have a higher nonce.
No. We need to REPLACE the existing transaction with a new one, using the SAME nonce.
12/ But we don't want to replace it with the same transaction (for example, your NFT "Mint" transaction).
Why? Because that'll mean we'll just have to use the same (likely high) gas limit and for contract interactions, that could cost a lot of money.
13/ As noted above, instead we'll execute a simple ETH send transaction. This costs only a small amount of gas, so we can bump up our gas price (i.e. our "bid" to miners) so it confirms in super quick time.
Once it confirms, all being well, it should replace our stuck TX.
14/ How do you find the nonce? If you go to your Metamask, and click on your pending TX, it'll show right there in Metamask.
For example, in the screenshot below, we can see that the nonce is 738.
We'll want to take a note of this, because we'll use it later.
15/ Whilst we're using MyEtherWallet to "write" our transaction, ultimately we'll need to approve it, and set the nonce in MetaMask.
MetaMask doesn't allow you to set the nonce by default (as you can really mess things up if you don't know what you're doing!).
16/ However, we'll need that ability to pull off this little trick, so in MetaMask, do this:
(1) Click the picture in the top-right
(2) Click Settings
(3) Click Advanced
(4) Toggle "Customize Transaction Nonce", shown in the image below.
17/ Right. Now we're ready to execute our wizardry. 🧙
(1) Go to v5.myetherwallet.com
(2) Click "Access My Wallet"
(3) Connect via MetaMask (example ⬇️ )
(4) Accept Terms
18/ Once you're in, you'll want to click "Send Transaction" on the dashboard, as shown below.
19/ Now you're ready to send your TX. Honestly, because you're going to be setting your gas price, and nonce, in MetaMask, all you literally need to do is:
(1) Make sure the ETH amount is 0
(2) Make sure you put your own ETH address in the "To Address" field
20/ Once you're done, click "Send Transaction".
At this point, your MetaMask will pop up with the transaction to execute. Don't click "Confirm" just yet!
21/ First off, you'll see that the "Custom Nonce" field will now show in your TX. It should be one higher than the number you noted before.
You'll want to amend this so it matches the number you noted down earlier (i.e. the nonce of your pending transaction).
Example ⬇️
22/ Secondly, you'll note from the image above that the TX is a "Sending ETH" transaction, rather than a "Mint" transaction or whatever you were doing with your stuck TX.
As such, the estimated gas fee should be super low in comparison. That means you can up your gas price.
23/ As such, before you hit "Confirm", you might just want to hit "Edit" and then edit the suggested gas fee to provide for high gas, or even something just above high gas.
This will ensure that your "fake" replacement transaction will confirm as soon as possible.
24/ Once you're done, submit your transaction, and voila! All being well, your transaction should confirm quite quickly and, once it does, your original transaction will be effectively "cancelled".
25/ At this point, you can re-assess what you want to do next.
If the mint you were going for is still some way away from selling out, you might wish to just take a break, and wait until gas is more reasonable before you try again.
Or if it's sold out, maybe not.
26/ Please exercise caution when using this method. Messing with the nonce can be tricky if you get it wrong.
I take no responsibility for any mishaps! Hopefully, however, the above will be useful for those who are completely stuck.
It's certainly saved me a number of times!
27/ Thanks as always for reading my lengthy threads!
If you've found this useful, please do consider sharing it with friends / your favourite Discord community.
Any and all feedback appreciated too! 😄
Take care all! ❤️