Bitcoin Forum

hello, I have a question about how to cancel a transaction which already commited to mempool but not confirmed?

if there is no way or tool to cancel a tx, is it need to develop one?

To be clear, there is nothing like canceling a bitcoin transactions, what you can do is to double spend it to another or same address with a higher transaction fee than the initial one set for the transaction. This act is dependent on a the type of wallet you use, if the transaction wallet you use has the RBF bumping feee then you can double spend the already sent transaction that is if it hasn’t been confirmed yet.

What you do to like cancel that transaction is to spend it to the same address it is coming from with a higher transaction, this is what the cancel transaction feature you see on wallets do. But theoretically you can cancel an already signed and broadcasted bitcoin transaction.

You can use the above method if you wish use a self custodial wallet that allows fee bumping, but if it doesn’t then you will have to wait for the transaction to either be confirmed or be dropped; if the fee set is low.

If you use a wallet that supports the RBF feature, you can cancel transactions that have been broadcast to your own address by increasing the fees. Apart from that, to speed up transactions, you can also use the RBF feature to increase transaction fees. To be able to do this, you must have remaining bitcoins in your wallet, otherwise you cannot do it

To see how RBF works, you can check out this thread : https://bitcointalk.org/index.php?topic=5422456.0

thank for the detailed explanation. I will go to take a look at the RBF feature

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Thank you very much.

Another question: so it means the transaction may be dropped if the fee is too low?

If the transaction fee is too low and unfortunately the mempool congestion doesn’t reduces such that the transaction fee rate comes down to your range of fee then the transaction will be dropped. The default time is (24) 14 days from the day you broadcasted your transaction but it varies because nodes have different mempool settings so could still have it beyond those days which extends the time for it to be dropped. Also the wallet you might be using could have an in built rebroadcasting feature which will continually rebroadcast your transaction and then stopping it from getting dropped

Look into ViaBTC accelerator (https://www.viabtc.com/tools/txaccelerator) to see if you meet the conditions to use the free acceleration service

To use RBF feature, your transaction must be RBF opt-in.

Did you broadcast your transaction initially with RBF opt-in? If wallet you use has an opt-in RBF, your transaction will have it with default setting.

If you are unsure, you can copy and paste your transaction id to https://blockchair.com/bitcoin and click on Additional information and see at a row for RBF Enabled

If your transaction is RBF opt-in, it will show as Yes.

Yes, and that is what is called purging. currently, the value is

https://www.talkimg.com/images/2023/12/25/IsrKP.png

so every node that uses the default size of 300MB will drop the transactions that have fees of less than 23.2sat/vb but nodes use custom mempool size so the transaction will likely stay longer because it stays in some nodes.

@OP you can replace your transactions, but make sure the next transactions you use the same inputs like your previous transactions.

But not all transactions that exceed the mempool size will be dropped, your transactions could be re-broadcast by your wallet or other nodes.

You can use wallet like Electrum or Sparrow to do that. But as Zaguru said, it is not actually cancel transaction, it is also a replace-by-fee transaction in a way the coin would be sent to one of your wallet addresses that you make the transaction from.

There are some wallet that support replace-by-fee to pump fee but not having it to cancel a transaction.

Typo, you meant 14 days, not 24 days. What to take note also is the purging. If the purging becomes higher than the fee rate used for the transaction, the transaction will also be dropped from the mempool.

Once a transaction is recorded in Mempool there is no way to cancel it. However, you can control the speed of this transaction by reducing and increasing the transaction fee. And if your transaction is pending for a long time for a small transaction fee and the block is not confirmed, then it will automatically fail the transaction. But you cannot cancel the transaction manually. This is because Bitcoin cannot be controlled by anyone, it is completely decentralized.  You can't control it at will, it runs on its own rules

As far as I know, once you have entered the pool, there is no way to cancel the transaction. The RBF feature only provides the option to increase or decrease transaction fees as far as I know and does not effectively cancel transactions, if the fee is increased there is a possibility that the transaction will be confirmed more quickly.

We recommend that before sending Bitcoin, we independently check whether the network is congested or not, whether the transaction fee has increased or not to expedite the sending process so that it is fast.

The only way now is to wait for the transaction to be confirmed, it may take 1 or 2 days 😅

Also to prevent this rebroadcasting, don't open your wallet also as wallets with this auto feature will keep broadcasting your unconfirmed transaction.

If you really need to check, just go offline and open wallet. 24 days is a loooong time, I know :)

That’s a typo, the default is 14 days and not 24 days which is still subjected to the conditions stated above

It's possible that most of the nodes drop your transaction from their mempool, but there is no guarantee that it won't be confirmed.
As long as there is no other confirmed transaction invalidating that transaction, there's a chance that the transaction is confirmed.

If you have broadcasted a transaction and you want to make sure that it won't be confirmed, you must create a new transaction using the same input and invalidate that.
Provided that the transaction is still valid, it may be confirmed one day even if you broadcasted it months ago and your wallet doesn't show it anymore.

That is why I said nodes uses custom mempool size will have OP's transaction. Rebroadcasting is another issue and some shitty custodial wallets and exchanges doing it to keep the transaction in the mempool even when they used  5/10sat/vbyte for the transaction with hundreds of inputs.

Not like dropped more like it's too slow that when it resolves the bitcoin that had RBF applied meant that when it was delivered it got no bitcoin to deliver anymore. Think of it this way, you ask for someone to deliver you a package but they take about 3 days to arrive to get the package and deliver it to the address so you hire another one that will deliver it to the same address (same address for the sake of example) but this time they arrive in 12 hours but you have to pay more because they're faster.

If you transact with mempool extra low, if mempool doesn't reach your set level, then after some time, your transaction may be canceled automatically, but once you submit the transaction, you may not be able to manually delete the transaction again. At present transaction fee is extra so we have to face many problems in transferring btc but if we try to transfer bitcoin by keeping mempool under regular monitoring then maybe it is possible to do bitcoin transaction with relatively less transaction fee. There are many people who have transferred bitcoins for important work but their transactions are still pending due to high transaction fees and this is a common problem nowadays.

Quick answer: Yes.
The fees now are quite lower compared to the past weeks that we've got. Post your TXID and let's see how much you've paid for the fee if it's way too low with what's mempool's fee being asked.

Or it may take longer than that.

You won't believe me guys, mine was more than that and the network really tested my patience back then.

If it is more than that, it means that the BTC network is very congested. This is very, very torturous if we really need money or Bitcoin, maybe RBF can really help overcome problems like this. Does BRC-20 exacerbate Bitcoin's current network congestion?

Difficulty adjustment right now isn't that much so if OP can simply put his TXID here, we can see if it's already confirmed or not. And depending on the fees on how low it is because it is also changing from time to time.

That's true, so plan your transactions and pay what's being required and/or use viabtc's help as long as your transaction is suiting the requirement of it for being accelerated.

Yes.

I don’t think difficulty adjustment has much of a thing to do about bitcoin congestion. Rather it is to adjust the average time it is expected to get a block confirmed to the default time of 10 minutes. This changes is caused by either a higher hashrate or a lower one. This adjustment helps to keep in check some bitcoin protocols like the halving period which happens every four years. The only thing that actually reduces the congestion on the mempool is when lesser transactions are made.

Also it is not just advisable to OP to just show his TXID everywhere as it can affect its privacy rather he can simply use the block explorer himself to check the status of the transaction

With this tip, I recommend using ViaBTC's paid service. I tried using their free service once and it takes an awful lot of time to have one free chance to accelerate your transaction. There is Binance's transaction accelerator, too, though they use flat fees most of the time and it's a lot more expensive to use than ViaBTC's service. There used to be tons of free transaction accelerator services out there, but apparently most have disappeared or become paid once the problem with high transaction fees began to linger bitcoin recently.

So the transaction will be dropped just meet one of the following conditions, is it right?

1. purging: take the above figure as an example, every node that uses the default size of 300MB will drop the transactions that have fees of less than 23.2sat/vb.

2. drop: the default is 14 days which is still subjected to the conditions stated above reply, which depends on node's config.

Yes, nodes have their custom setting, mempool size but nodes will drop the transactions which is unconfirmed for 14 days or above unless it is rebroadcasted or the transaction can be dropped earlier too, if the fee used is far less than the purging rate.

Bitcoin transactions are irreversible. That means once you send it, you can’t reverse it back. Yes what you can do is that, if it hasn’t got any confirmations in blockchain network, then you can use Replace By Fee feature if your wallet supports to increase the fee and speed up the transaction. That’s the only action possible and that too with specific wallets. Otherwise you can try transaction accelerators to accelerate any stuck transactions in the worst case.

Yeah, there is no way to cancel the transaction when it is already in a pending state. I was also shocked when I came to know about it, actually, I was making transactions before knowing it, but one day my transition for BTC was taking a long, and for the very first time it took around 3 to 4 hours and I was damn worried about the transaction. Then I did some research and came to know about the transaction's states.

Actually, I was already aware of them but did not come to think of them at that time, well, these states are pending, completed, and Revoked which means, that when you have made the transaction, it goes to the pending state and it can not be canceled and after it will be either completed or revoked if found some error by the miner/validators.

It is the same as a transaction which has some database features. This means a transaction in progress can not be reversed or canceled because it would cause so much trouble like the biggest one is getting scammed or doing scams etc. The result is, cancel feature can't be added (AFAIK).

That's just if he doesn't know how to accelerate it and someone can do it for him but then, I don't disagree with you because you're right that his privacy will be defeated if he shared it to us. I don't have any bad intention with that because we usually see newbies don't know how to accelerate their transactions and aren't aware that they've paid so low fee.

I've used it for many instances and it did really helped me the most. But as the fees are adjusting again and they're increasing as per checking it, the free acceleration is always out and that's why if someone like OP or anyone out there wants to use the free one, you'll need to be faster than anyone else before it refreshes to 00:00 time.

I've used Binance accelerator too and it did helped me as well with my so loooong stucked transaction. It is more expensive but I'd say that it's worth the buck for the delay that it has caused me.

Good question and conclution. While the transaction may be rebroadcasted by node or some wallets sometimes.