How to modify or cancel a pending Ethereum transaction


Ethereum is an open source blockchain-based software platform with thousands of decentralized applications (DApps) that power its native cryptocurrency, Ether (ETH), which can be sent and received around the world without any interference from third.

First designed in 2013 by Russian-Canadian programmer Vitalik Buterin, Ethereum was designed as a platform for self-executing, permanent, and immutable DApps with use cases ranging from finance to gaming and business. ‘art.

DApps are often referred to as smart contracts, which are Ethereum transaction protocols that automatically perform certain functions and actions such as processing transactions with predetermined conditions and agreements. Sending a transaction, canceling it, 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 deployment transactions, the receiver-less transaction type, and regular transactions, the simplest type of transaction used to transfer ETH from a wallet to a wallet. other.

A submitted regular Ethereum transaction includes the sender ID or 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 amount of ETH to transfer from sender to recipient, information about Ethereum transaction fees, and an optional field to include arbitrary 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 in order to receive a reward for their work in creating new ETH. When a miner solves a cryptographic (mathematical) puzzle, a transaction is considered committed. Ethereum, like Bitcoin (BTC), has a Proof of Work (PoW) system to prevent cyber attacks from a single individual or group.

Requiring users to pay transaction fees while using the blockchain protects the Ethereum network from botched or malicious computational tasks such as users spamming the blockchain with unnecessary transaction overload.

Ethereum transaction lifecycle

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

Unknown: Unknown state refers to a transaction that the network has not seen or processed.

Waiting: When a transaction is pending, it waits for miners to retrieve and process it, known as a bulk transaction, also known as a “mempool”. As miners prioritize higher gas prices, transactions with lower gas values ​​may languish in the waiting phase for an extended period of time. Transactions with the lowest gas prices may never be recovered, leaving them “stuck” in the pending status forever.

In block: When a miner successfully selects a transaction and operates it in a block, it enters the state in the block. Bulk transactions are called mined transactions. If the block is forked, a transaction in the block can revert to the pending state. When a mined transaction (i.e. a transaction in the block state) is reversed by the network, it is known as a forked transaction.

Replaced: When any of the following circumstances occur, a transaction can be moved from the pending state to the replaced state:

  • A new transaction with the same nonce from the same sender goes into the blocked state, or
  • Another transaction with the same nonce and a gas price 12% higher enters the waiting phase, this time from the same shipper.

Ethereum transaction confirmations

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

A pending Ethereum transaction should receive a number of confirmations. The higher the gas charge, the greater the certainty that the Ethereum network has processed and acknowledged the transaction.

Recent blocks may be rearranged, giving the impression that the processing of the transaction has failed. Even so, the transaction can be included in another block and remains valid. The probability of reorganization decreases with each block mined thereafter, i.e. the more confirmations there are, the more the transaction becomes immutable.

Ethereum transaction confirmations

A transaction fee is an incentive paid by users to block minors. It is used to send a particular transaction to the Ethereum blockchain.

Ethereum blockchain transaction fees are also referred to as gas fees because they are tied to gas, a pricing mechanism used on the Ethereum network that refers to the computation required to process the transaction by a miner. The calculation tasks of a transaction are measured in terms of the cost of gas.

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

What is a nuncio?

A nonce is the abbreviation for “number used only once”, referring to the total number of confirmed transactions sent from the given Ethereum address.

Ethereum wallets can broadcast multiple transactions from one account without too much delay between them, which means that a nonce calculation is considered a necessary mechanism that determines which transaction is processed first. Usually, Ethereum wallet apps take care of nonce management for users.

How to cancel an Ethereum transaction?

There are two main ways to roll back a pending Ethereum transaction: rollback in the app and setting a custom nonce.

Usually, Ethereum transactions are on hold for hours or stuck when users submit with a low gas price. Therefore, users often find it necessary to modify Ethereum transactions.

When troubleshooting this issue, users should remember that rollback can only be attempted if the transaction is still pending on the network. The first step is to check in a block explorer if the transaction is still pending. Mainly, to paste the hash of the transaction, also known as the Ethereum transaction ID, and if a block explorer says “pending”, users can always try to roll it back.

The easiest way to void a stuck Ethereum transaction is in-app void, which requires users to exit the Ethereum wallet app and close their browser, reopen it, and log back into the app. .

If these steps do not solve the problem, the second way will come to the rescue.

Canceling a pending Ethereum transaction by setting a custom nonce means generating a 0 ETH transaction with a high gas price at the user’s own address to prevent a previous transaction from being blocked. Before sending this second transaction, users should note the nonce used by the original pending transaction, and then reuse the same nonce they wrote down.

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

How to speed up the Ethereum transaction?

Users can speed up a slow Ethereum transaction by adding gas to it. This step may cause Ethereum miners to prioritize it.

If an Ethereum user prices gas too low, other users have the option to outbid that initial offer and the transaction will remain on hold. When the transaction is blocked, the network does not confirm any new transactions from the same wallet address until the miner confirms the first transaction.

In this situation, users can choose to wait for the network to agree to process a transaction at the set price or resubmit the original transaction, but with higher gasoline charges. Clicking on the ‘speed up’ button in their Ethreum wallet should allow the transaction to be processed faster.

If the previous step did not work, users could go to the advanced tab to set the gas price manually.

After all, users are advised to search the blockchain explorer for the transaction by posting its hash to see if it was processed successfully. If the transaction does not appear immediately, they will have to wait a few minutes and refresh a page.

Can Ethereum transactions be rolled back?

Ethereum wallets cannot cancel Ethereum transactions that have already been completed.

When Ethereum users accidentally send funds to the wrong address or send the wrong amount of ETH, they can cancel the transaction while it is still pending. When the transaction is confirmed and displayed as “successful”, which means it has been added to the next block, it cannot be rolled back. The Ethereum blockchain is designed to be immutable, so that the blocks of data entered are irreversible. Knowing this, it is essential to make sure that the transaction details are correct before clicking on the submit button.

Finally, it should be noted that many blockchain startups have already developed mechanisms that would allow users to reverse Ethereum transactions.