How to change or cancel a pending Ethereum transaction


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Ethereum is an open source blockchain-based software platform with thousands of decentralized applications (DApps) that powers its native cryptocurrency Ether (ETH), which can be sent and received worldwide without third-party intervention.

Ethereum was first conceived in 2013 by the Russian-Canadian programmer Vitalik Buterin and designed as a platform for self-executing, permanent and immutable DApps with use cases from finance to games to art.

DApps are often referred to as Smart Contracts, which are Ethereum transaction logs that automatically perform certain functions and actions like transaction processing with predetermined terms and agreements. Sending a transaction, canceling or resolving a pending Ethereum transaction are actions related to how smart contracts work.

What is an Ethereum transaction?

Transactions are cryptographically signed instructions from accounts.

The Ethereum network supports two main types of transactions: contract delivery transactions, the type of non-recipient transaction, and regular transactions, the simplest type of transaction used to transfer ETH from one wallet to another.

A submitted, regular Ethereum transaction contains the sender’s identifier or the signature generated when the sender’s private key signs the transaction and confirms that the sender has authorized the particular Ethereum transaction. The receiving address, an ETH amount to be transferred from the sender to the recipient, information about the Ethereum transaction fee and an optional field for entering any data are all part of a submitted regular Ethereum transaction.

Ethereum transactions must be mined to become valid and require a fee from the sender.

Ethereum miners verify legitimate transactions for a reward for their work in creating new ETH. When a miner solves a cryptographic (mathematical) puzzle, a transaction is considered validated. Like Bitcoin (BTC), Ethereum has a Proof-of-Work (PoW) system to prevent cyberattacks by a single person or group.

Requiring users to pay a transaction fee when using the blockchain protects the Ethereum network from sloppy or malicious computing tasks such as users spamming the blockchain with an overload of useless transactions.

Ethereum Transaction Life Cycle

An Ethereum transaction goes through a series of states, starting with the unknown state, until it is confirmed in a block.

Unknown: The unknown state refers to a transaction that the network did not see or process.

Pending: When a transaction is pending, it waits for miners to pick it up and process it in what is known as a pooled transaction, also known as a “mempool”. Since miners prioritize higher gas prices, transactions with lower gas values ​​can remain in the pending phase for a longer period of time. The transactions with the lowest gas prices may never be picked up and remain in a pending state forever.

In the block: If a miner successfully selects a transaction and mines it within a block, it goes into the in-block state. In-block transactions are known as mining transactions. When the block is forked, a transaction in the block can return to the pending state. When a shutdown transaction (i.e., one in the block state) is rolled back from the network, it is known as a forked transaction.

Replaces: A transaction can be moved from the pending state to the replaced state if any of the following occurs:

  • A new transaction with the same nonce from the same sender changes to the block state, or
  • Another transaction with the same nonce and a 12% higher gas price goes into the pending phase, this time from the same sender.

Confirmations of Ethereum transactions

Ethereum transaction confirmations are the number of blocks created since the first block that contained this transaction.

A pending Ethereum transaction must receive a certain number of confirmations. The higher the gas fee, the greater the certainty that the Ethereum network has processed and recognized the transaction.

Recent blocks can be reorganized, giving the impression that transaction processing has failed. Nevertheless, the transaction can be included in another block and remains valid. The probability of a reorganization decreases with each subsequent block that is cleared, ie the more confirmations, the more unchangeable the transaction becomes.

Ethereum transaction confirmations

A transaction fee is an incentive that users pay to block miners. It is used to send a specific transaction on the Ethereum blockchain.

The Ethereum blockchain transaction fees are also known as gas fees as they refer to gas, a pricing mechanism used on the Ethereum network and related to the calculation required for a miner to process the transaction. The computing tasks of a transaction are measured using the gas costs.

On the other hand, every gas unit has a gas price that is given in ETH. Although the complexity of a particular transaction determines the cost of gas, users can set their own price and gas limit, or the maximum amount of units of gas consumed by the transaction.

What is a nonce?

A nonce is an abbreviation for “Only used once” and refers to the total number of confirmed transactions sent from the given Ethereum address.

Ethereum wallets can transfer multiple transactions from one account to one another without much delay, which means that a nonce calculation is seen as a necessary mechanism that determines which transaction will be processed first. Usually, Ethereum wallet applications take care of nonce management for users.

How do I cancel an Ethereum transaction?

There are two main methods of canceling a pending Ethereum transaction: canceling it from within the application and setting a custom nonce.

Typically, Ethereum transactions are pending or stuck for hours when users submit with a low gas price. Hence, users often find it necessary to change Ethereum transactions.

In solving this problem, users must keep in mind that a void can only be attempted if the transaction is pending on the network. The first step you need to take is to check in a block explorer to see if the transaction is pending. Mainly to insert the transaction hash, also known as the Ethereum transaction ID, and if a block explorer says “pending”, users can still try to cancel it.

The easiest way to abandon a stalled Ethereum transaction is to cancel within the application, which requires users to exit the Ethereum wallet application and close their browser, reopen it and log back into the application.

If these steps don’t solve the problem, then the second route to salvation will come.

Canceling a pending Ethereum transaction by setting a custom nonce means that a 0 ETH transaction with a high gas price will be generated to the user’s own address to prevent a previous transaction from getting stuck. Before submitting this second transaction, users must write down the nonce used by the original pending transaction and then reuse the same nonce that they wrote down.

If users have multiple pending Ethereum transactions, they preferably start with the oldest or lowest nonce value.

How do you speed up the Ethereum transaction?

Users can speed up a slow Ethereum transaction by adding gas. This step can inspire Ethereum miners to set priorities for them.

If an Ethereum user sets a gas price that is too low, other users have the option to outbid that original bid and the transaction will remain pending. If the transaction gets stuck, the network will not confirm any new transactions from the same wallet address until the miner confirms the first transaction.

In this situation, users can either wait until the network is ready to process a transaction at the set price, or resubmit the original transaction, but with a higher gas fee. A click on the “Accelerate” button in your Ethreum wallet should enable the transaction to be processed more quickly.

If the previous step didn’t work, users can go to the Advanced tab to manually set the gas price.

Finally, users are advised to search the transaction in the blockchain explorer by posting their hash to see if it has been processed successfully. If the transaction does not appear immediately, you will have to wait a few minutes and refresh a page.

Can Ethereum transactions be reversed?

Ethereum wallets cannot undo already completed Ethereum transactions.

If Ethereum users accidentally send money to the wrong address or send the wrong amount to ETH, they can cancel the transaction while it is pending. If the transaction is confirmed and shown as “Successful”, which means it has been added to the next block, it is irreversible. The Ethereum blockchain is designed to be immutable, so the data blocks entered are irreversible. With that in mind, it is important to ensure that the transaction details are correct before hitting the Submit button.

Finally, it’s worth noting that many blockchain startups have already developed mechanisms that would allow users to reverse Ethereum transactions.