If you have ever sent two transactions close together and watched the second one just sit there, waiting, even though it had plenty of ETH for gas, you have run into the nonce system. It is one of the more invisible parts of how a wallet works, and it explains a whole category of confusing behavior once you understand it.
What a nonce actually is
A nonce is simply a count. Every account on Base has one, and it starts at zero. The first transaction you ever send from that address has nonce 0. The second has nonce 1. The third has nonce 2, and so on. Every new transaction increases the count by exactly one.
The word itself comes from "number used once," and that is the whole idea. Each nonce value can only be used a single time by a single account. Once nonce 4 has been used, it can never be reused for that account again.
Your wallet handles this for you automatically. You never type a nonce in when you send a transaction or confirm a swap. But behind the scenes, every transaction you sign includes this number, and the network relies on it completely.
Why the network cares about order
Networks like Base need a way to know the order you intended your transactions to happen in, especially if you send several close together. The nonce is that mechanism. The network will only process a transaction with nonce 5 after it has already processed the transaction with nonce 4 from that same account. If nonce 4 has not gone through yet, nonce 5 waits, no matter how much gas you offered or how simple the transaction is.
This is different from how a block explorer might show things visually. Transactions can look like they are all sitting in a queue together, but really it is a strict, ordered line. One at a time, in sequence, per account.
Why this causes "stuck" transactions
This is the part that trips people up. Say you send a swap, and for some reason it does not confirm quickly, maybe the gas offered was too low, or the network was briefly congested. That transaction used nonce 7. If you then try to send another transaction, say sending a token to a friend, your wallet assigns it nonce 8.
Nonce 8 cannot go through until nonce 7 is resolved, one way or another. So your second transaction appears stuck, even though nothing is wrong with it specifically. It is not broken. It is simply waiting its turn behind an earlier transaction that has not finished yet.
This is one of the most common sources of confusion for people newer to self-custody wallets. A transaction that looks frozen is often just queued behind a sibling transaction from the same account.
How this normally resolves itself
On Base, this situation is usually short-lived. Base processes blocks quickly and fees are low, so a transaction with a reasonable gas setting typically confirms within a few seconds. Most of the time, nonce 7 clears on its own, and nonce 8 follows right behind it without you having to do anything.
The advice for a genuinely stuck earlier transaction is patience first. Sending more transactions on top does not help, since each new one just takes the next nonce in line and waits behind the same jam. If a transaction has been pending for an unusually long time, the two real options are to wait it out or to replace it, which some wallets support by resubmitting the same nonce with a higher fee so the network processes the replacement instead.
Where you might actually see a nonce
Most people can use a wallet for years without ever looking at a nonce directly, and that is by design. But if you ever open a transaction on a block explorer like BaseScan, you will see the nonce listed as one of the transaction details, right alongside the gas fee and the block number. It is a useful thing to glance at if you are trying to understand why a transaction is taking a while, since it tells you exactly where that transaction sits in your account's queue.
If you want to get comfortable reading these details yourself, our guide to using a block explorer walks through what each field on a transaction page means.
Why this design exists at all
It might seem simpler if transactions from an account could just process in any order, whichever confirms first. But that would create real problems. Without a strict order, it would be possible to accidentally submit conflicting transactions, for example spending the same funds twice in two different ways, and have the network process them unpredictably. The nonce system removes that ambiguity entirely. Your account's history becomes a clean, unambiguous sequence, which is part of what makes a blockchain reliable to build on.
The calm summary
A nonce is just a counter that keeps your transactions in the exact order you sent them. Transactions from your account are processed one at a time, in that order, and nothing later in the line can jump ahead of something earlier that has not finished. If a transaction ever looks stuck for no obvious reason, the nonce system is often the explanation, and the fix is almost always to be patient with the transaction ahead of it rather than to keep sending new ones.
Sources: Ethereum.org developer documentation on transactions, Base documentation