Blockchain is characterized by immutability and transparency. This means that it is almost impossible for information on the network to be edited or tampered with. Therefore, it is crucial to verify the data before signing a transaction, because once the operation is confirmed and added to the block, it is impossible to cancel it.

Is it possible to cancel a blockchain transaction?

In general, cryptocurrency transactions cannot be edited or changed in any way. However, there is a chance to cancel a transaction before it is included in a block and enters the memory pool to wait for its turn.

Depending on the capabilities of a particular blockchain and the network load, the confirmation time of a transaction will vary. For example, in the Bitcoin network, this can take up to 20 minutes.

Transactions can also become "hanged" in the network for the following reasons:

• Insufficient transaction fees

• Network overload

• Attempting to use recently transferred digital assets

• Technical issues

Therefore, the only way to cancel a transaction in a public blockchain such as Bitcoin or Ethereum is to do so within the interval between signatures and confirmations in the network.

How do I cancel a blockchain transaction?

Canceling a transaction can be difficult, as it often requires special knowledge and understanding of the steps involved in resolving the issue.

Some blockchains may have built-in mechanisms for changing transactions. However, in this case, success or failure depends on many factors, such as the state of operation and the type of network. In private blockchains, it may be easier to cancel transactions, as the network is centrally controlled and the administrators theoretically have the power to cancel the operation.

Transactions can be canceled by:

• Using built-in mechanisms

• Sending a new transaction with the same details but with a higher fee to "push" the operation

• Contacting the network administrator (for private blockchains) or an expert

The sooner a user takes steps to cancel a transaction, the greater the chances of having it reversed. If for some reason the operation is not canceled in time, it is worth considering contacting the recipient directly and asking them to return the assets.

If a user transfers cryptocurrency to an invalid address, the funds may be automatically returned or lost forever, depending on the protocol.

Let's see how to cancel a transaction in different situations.

Canceling a Transaction in MetaMask

In the MetaMask crypto wallet, there are two ways to cancel a transaction.

The first and easiest way is to use the built-in function.

To do this, in the transaction window, click on the "Cancel" button and then click on "Submit" to sign the transaction, as shown in the screenshot below.

There is another way to cancel an unconfirmed transaction - sending an "empty" transaction to your own address. The process is more complicated.

First, please note that each transaction has a unique identifier, called a nonce. To cancel a pending transaction, you need to send another transaction to your own address. In this process, you must specify the nonce of the operation you want to cancel.

However, this is considered an advanced feature, so you need to activate it in the advanced settings to manage identifiers.

To set the nonce in MetaMask:

1. Click the three dots in the upper right corner and select "Settings":

2. Go to "Advanced":

3. Scroll down and enable the nonce option by finding "Custom transaction nonce":

4. After this, each transaction can set a nonce:

In order to "push" the required operation, it is crucial to set a higher gas fee. The MetaMask team recommends increasing the fee by at least 30% compared to the previous transaction.

So, while the first method requires fast action, it is definitely better!

Canceling a transaction in the Bitcoin network

To cancel a transaction in the Bitcoin network, it is usually necessary to check the status of the operation. This can be done in a block explorer such as Blockchain.com by entering the transaction identifier (TxID) in the search bar:

If an operation has received at least one confirmation, it no longer makes sense to try to cancel the transaction. However, if the number of confirmations is zero, you can try to cancel it.

If an operation has received at least one confirmation, it no longer makes sense to try to cancel the transaction. However, if the number of confirmations is zero, you can try to cancel it.

Users can choose a strategy that suits them:

• Replacement by Fee (RBF) protocol — allows replacing the original transaction with a new one by increasing the transfer fee. However, not all wallets support RBF, so it is recommended to check the parameters first;

• Double spending — in this case, a transaction can be canceled by trying to transfer a similar amount of BTC to one's own address. In the best case, miners will process the last transaction. However, it is worth noting that most nodes and crypto wallets have built-in protection against such operations.

About canceling Ethereum transactions

In Ethereum, in order to cancel a transaction, a new transaction with the same initial data is usually created, but with an increased fee. This method speeds up the processing of new transactions, while previous transactions are not recorded in the blockchain.

Transactions can also be overwritten using a nonce. In this case, the user initiates a new operation to his address and specifies the nonce of the previous transaction.

In special cases, transactions can be canceled using smart contracts. Some of these contracts contain functions to cancel operations if the transaction conditions are not met.

Conclusion

Thus, canceling a transaction requires quick and swift action. After all, most transactions in popular networks usually occur instantly and cannot be reversed.

This blockchain approach aims to maintain and enhance the security of decentralized networks.