Good morning.
I’m Mitsui, a web3 researcher.
Every Saturday and Sunday at noon, we’ll deliver articles explaining basic vocabulary. We aim to keep each article concise enough for a quick read, while also providing content you can revisit and study.
Today’s word is “Nonce.”
Please watch until the very end!
Introduction｜Why Transactions Get Congested on Ethereum
One of the most frustrating experiences when using Ethereum is encountering situations where “transactions don’t go through.” You send a transaction from your wallet, yet it remains pending for hours. Or, you send multiple transactions, but only some fail. When faced with these issues, many people assume “the Ethereum network is congested” or “the gas fee is too high.”
However, the actual cause lies entirely elsewhere. That is the Nonce.
The nonce is a concept rarely displayed on wallet screens and seldom consciously considered, yet it is a system that always functions when sending transactions on Ethereum. The nonce is like an invisible backbone that ensures the consistency of your account’s actions.
Understanding the nonce reveals that many seemingly strange behaviors in Ethereum are actually the result of rational design choices. It also clarifies how to handle situations when transactions become congested. For web3 beginners, the nonce is one of the first concepts you should grasp.
What is a Nonce? | Definition and Mechanism
A nonce (number used once) is a sequential number assigned to transactions sent from a specific address. The first point to understand is that a nonce has absolutely nothing to do with cryptography. A nonce is simply a sequence of numbers.
Let me explain in detail.
When your address sends its first transaction on Ethereum, the Nonce value for that transaction is 0. The Nonce for the next transaction you send will be 1, then 2 for the following one. It will increase by 1 each time you send a transaction thereafter. This simple mechanism plays an extremely important role in maintaining the overall order of the Ethereum network.
The key point is that the Nonce is managed per account. The Nonce for Address A and the Nonce for Address B are completely independent. Furthermore, the Nonce increases regardless of whether the transaction succeeds or fails. Even if a transaction fails, a used Nonce cannot be reused for the next transaction.
Equivalent in Web2｜Number management existing around us
Nonce actually exists in the Web2 world as well. In fact, it’s a concept that exists everywhere in Web2.
Consider making a bank transfer. When you go to the bank to request a transfer, you are issued a queue number. This is a sequential number assigned to your transfer request, and bank staff use this number to manage the order of processing.
Similarly, when you purchase an item through online shopping, an order ID is issued. This ID is a unique identifier assigned to your order request. Developers using APIs also manage multiple requests using request IDs.
The purpose of all these systems is the same.
These are two principles: “Do not process the same operation twice” and “Maintain the exact order of processing.” If the same bank transfer were executed twice, it would be a major problem.
On e-commerce sites, it’s problematic when the same order is processed multiple times. In Web2, such number management systems are operated by a central authority. Trusted central authorities—such as bank employees, e-commerce site administrators, and API servers—assign numbers to maintain order.
The fundamental difference in Web3 is the absence of this central authority. So who assigns the numbers? The answer is self-declaration by the users themselves—that is, the Nonce.
Why is a Nonce Essential in Blockchain?｜Order in a World Without Central Administrators
Ethereum possesses a major feature not found in traditional systems.
First, there is no central authority determining the processing order. While banks have bank employees, Ethereum has no equivalent administrator. Second, numerous nodes perform verification tasks simultaneously. While a single system handles processing in banks, thousands of nodes worldwide verify the same transactions in Ethereum.
In this structure, someone must decide which transaction comes first. How can this order be determined in the absence of an administrator? The answer is for each account to assign a number to its own transaction. That is, the account declares, “My first transaction is Nonce0, and my next transaction is Nonce1.”
The validator checks the Nonce value when receiving a transaction. If it matches the expected Nonce value (previous Nonce + 1), the transaction is valid.
If they do not match, they must be processed later. This simple mechanism maintains order without administrators. The nonce is a self-declared ordering system in a trustless world.
What Happens Without a Nonce｜A Chain of Serious Problems
Imagine a world without nonces. Understanding the chaos that would ensue makes the importance of nonces abundantly clear.
First, it becomes possible to send the same transaction multiple times. Suppose you create a transaction to send 1 ETH. It should only be executed once.
However, without a nonce, the same transaction could be sent multiple times to the network. As a result, instead of 1 ETH, 3 ETH might be sent. This double-spending problem is a fundamental threat to blockchain.
Next, it enables “replay attacks” that allow past transactions to be executed again. Attackers can capture past transaction data and resend it, enabling fraudulent transactions to be carried out.
Furthermore, the integrity of the account balance completely breaks down. Even basic information like “what is the current balance?” becomes unreliable. Because the sequence of who sent money, when, and how much becomes unclear, calculating the final balance becomes impossible.
These issues represent not merely security vulnerabilities, but a fundamental disruption that could undermine the very existence of the blockchain system itself.
You don’t know how many times a transaction will be executed, you don’t know when it will be executed, and you don’t know how much will ultimately be deducted. Who would place trust in such a system? The nonce is the minimal defense line to prevent all these problems.
Relationship Between Nonce and Other Concepts｜Comprehensive Understanding of Web3
A nonce does not function in isolation but is closely intertwined with other key concepts in web3. Understanding these relationships reveals how web3 operates as a whole.
A transaction represents any operation executed on the Ethereum blockchain. Sending funds, executing smart contracts, transferring tokens—all of these are transactions. And every transaction contains a parameter called a Nonce. A transaction cannot be completed without a Nonce.
When considering accounts, the Nonce is account-specific information. Even on the same Ethereum network, the Nonce for Address A and the Nonce for Address B are completely independent. Understanding the Nonce is also understanding the essence of account management.
The mempool is where transactions wait before being included in a block. Transactions with incorrect nonce sequences remain stuck in the mempool. For example, if a transaction with Nonce 2 is sent before Nonce 0 is confirmed, Nonce 2 will continue to wait in the mempool. If the nonce sequence is not complete, mempool efficiency is significantly reduced.
Gas fees are the charges required to execute transactions, but no matter how high the gas fee you pay, you cannot skip the nonce sequence. This is the point most beginners misunderstand. While a high gas fee increases priority, without the correct nonce value, you can’t accomplish anything.
In other words, a nonce is an “invisible constraint that binds the whole.” It doesn’t appear on the front stage of web3, but it supports the order of the entire system behind the scenes.
The Web3 Value Symbolized by Nonce｜A World of Self-Governed Rules
A nonce is merely a number, yet it symbolizes the essence of web3 philosophy. It embodies the concept of “the minimal rules needed to maintain order in a world where no one is in charge.”
In the traditional financial system, a central authority—the bank—determined “what the next number would be.” Vast numbers of bank personnel and systems were dedicated to maintaining this order.
In Ethereum, this role is handled entirely by automated code and numbers. Validators simply verify the Nonce value. There is no room for judgment or discretion.
Understanding this mechanism makes it abundantly clear that web3 is not simply about “freedom,” but rather a world where you take responsibility for the rules yourself. On Ethereum, instead of having a central authority, every user bears the responsibility for maintaining order.
The true value of Web3 lies in liberation from central authorities. Nonce is an extremely practical and rational mechanism that symbolizes both aspects.
Disclaimer：I carefully examine and write the information that I research, but since it is personally operated and there are many parts with English sources, there may be some paraphrasing or incorrect information. Please understand. Also, there may be introductions of Dapps, NFTs, and tokens in the articles, but there is absolutely no solicitation purpose. Please purchase and use them at your own risk.
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🇯🇵🇺🇸🇰🇷🇨🇳🇪🇸 The English version of the web3 newsletter, which is available in 5 languages. Based on the concept of ``Learn more about web3 in 5 minutes a day,'' we deliver research articles five times a week, including explanations of popular web3 trends, project explanations, and introductions to the latest news.
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mitsui
A web3 researcher. Operating the newsletter "web3 Research" delivered in five languages around the world.
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The author is a web3 researcher based in Japan. If you have a project that is interested in expanding to Japan, please contact the following:
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*Please note that this newsletter translates articles that are originally in Japanese. There may be translation mistakes such as mistranslations or paraphrasing, so please understand in advance.