Most transactions on Base confirm within a couple of seconds. Every so often, though, one just sits there. The wallet shows it as pending, the swap or transfer has not gone through, and nothing you do seems to change it. This guide covers why that happens, how to actually speed up or cancel a stuck transaction, and the situations where the only honest answer is to wait it out.
Why a transaction gets stuck in the first place
Every transaction your wallet sends carries a sequence number called a nonce. Your first ever transaction is nonce 0, your second is nonce 1, and so on, one number higher each time. Transactions have to be included in that exact order. If the transaction at nonce 5 has not gone through yet, nonce 6 cannot go through either, no matter how much you are willing to pay for it. It simply waits behind the earlier one.
We cover this mechanism in more detail in our article on transaction nonces, but the short version is what matters here: a transaction usually gets stuck because it offered too low a fee for current network conditions, and it is sitting in a queue rather than failing outright.
It is worth noting that this queue is not the kind of public, widely gossiped mempool that exists on Ethereum mainnet. Base runs on a single sequencer, and as we explain in our article on why Base does not have a public mempool, there is no open floor where outside parties can watch your pending transaction and act on it. There is still a local pending queue, ordered by nonce, that the node handling your transaction keeps before including it in a block, and that is the queue a stuck transaction sits in.
What "replacing" a transaction actually means
You cannot delete a transaction once you have signed and sent it. What you can do is send a new transaction that reuses the exact same nonce. Since a nonce can only be used once, the network accepts whichever version of that nonce it processes first, and the other one becomes invalid. That is the entire mechanism behind both "speed up" and "cancel" features in a wallet. Speeding up means sending a new version of the stuck transaction with a higher fee, so it goes through instead of the slow one. Canceling means sending a zero-value transaction to yourself, using the same nonce, so nothing happens except that the stuck transaction gets replaced with a harmless one.
The fee has to be meaningfully higher
You cannot replace a pending transaction with one that pays only a token amount more. Most nodes, including the software Base's infrastructure is built on, reject a replacement that is not enough of an improvement, usually returning an error along the lines of "replacement transaction underpriced." A common rule of thumb, based on the default settings in widely used Ethereum client software, is that the new transaction needs to offer at least about 10% more in priority fee than the one it is replacing, and it needs to cover the current base fee on top of that. If network conditions have shifted since you sent the original transaction, you may need to offer more than the minimum for the replacement to actually get picked up quickly.
How to speed up a transaction
The exact screen varies by wallet, but the steps are similar across most self-custody wallets you would use on Base:
- Find the pending transaction in your wallet's activity or transaction history.
- Look for a "speed up" option next to it. Most wallets only show this while the transaction is still pending.
- The wallet will suggest a higher gas fee, usually calculated to clear the minimum bump automatically. You can typically increase it further if the network is busy.
- Confirm and sign the new transaction.
- Wait for either the original or the replacement to confirm. Only one will.
If your wallet does not have a built in speed up button, some let you achieve the same result manually by sending a new transaction and setting the nonce field yourself in advanced settings, matching the nonce of the stuck one and increasing the gas fee.
How to cancel a transaction
Canceling works the same way, except the replacement transaction sends zero value to your own address instead of carrying out the original action. Most wallets offer a "cancel" button right next to "speed up" for exactly this purpose. It still costs a network fee to submit, since it is a real transaction that has to be processed like any other. What it saves you from is an unwanted action, such as a swap at a price you no longer want, actually going through.
When replacement will not help
A few situations are worth knowing about before you try:
The original already confirmed. If the stuck transaction gets included in a block moments before your replacement arrives, the replacement simply fails, since that nonce is no longer available. This is a normal outcome, not an error on your part, and any fee spent on the replacement in that case still applies since it was broadcast in good faith based on the information available at the time.
You are replacing the wrong nonce. If you have several transactions queued and you speed up or cancel the wrong one, only that specific nonce is affected. Everything behind it in the queue still waits its turn.
The transaction was going to fail anyway. If a swap was stuck because it would have failed for reasons unrelated to fees, such as a broken approval or a liquidity issue, speeding it up will not fix that. Our article on why a transaction fails on Base covers those causes separately.
Your wallet balance cannot cover the higher fee. A replacement transaction still needs enough ETH available to pay the new gas cost, on top of whatever the original transaction was moving.
The short version
A stuck transaction on Base is almost always a nonce sitting behind an underpriced fee, not a sign that something is broken. Speeding it up means resubmitting the same nonce with a meaningfully higher fee, and canceling means resubmitting that nonce as a harmless, zero-value transaction to yourself. Either way, only one version of a given nonce can ever go through, and checking that you are targeting the right pending transaction before you act will save you an unnecessary extra fee.