Why is my transaction stuck pending, and how do I speed it up or cancel it?

How to read that:

• The latest nonce is the nonce of the first unmined transaction. If that's not the transaction you're worried about, fix the earlier one first.
• If maxFeePerGas is below the base fee, you must replace it or wait.
• If cast tx finds nothing and the explorer doesn't know the hash either, the transaction has been dropped. Its nonce is free again, and you can simply send a new transaction with it.

Speed it up

Send the same transaction (same to, data, value) with the same nonce and higher fees. Nodes only accept a replacement if it pays noticeably more than the original. Geth's default requires at least a 10% increase on both maxFeePerGas and maxPriorityFeePerGas, and some nodes and providers require more. Otherwise you'll get replacement transaction underpriced.

In MetaMask and most wallets, the Speed up button does exactly this. From the command line with Foundry:

cast send $CONTRACT "claim(uint256)" 7 \
  --nonce 41 \
  --gas-price 40gwei \
  --priority-gas-price 3gwei \
  --account deployer \
  --rpc-url $RPC_URL

For EIP-1559 transactions, --gas-price sets maxFeePerGas and --priority-gas-price sets the tip. Choose a max fee comfortably above the current base fee, since you only pay the base fee plus the tip and the rest is not charged. --account uses an encrypted keystore created with cast wallet import, which is safer than pasting a private key into your shell history.

Cancel it

There's no cancel instruction in Ethereum. "Cancel" means replacing the transaction with one that does nothing: send 0 ETH to your own address with the same nonce and higher fees:

cast send $MY_ADDRESS \
  --value 0 \
  --nonce 41 \
  --gas-price 40gwei \
  --priority-gas-price 3gwei \
  --account deployer \
  --rpc-url $RPC_URL

This costs the base gas of a plain transfer (21,000 gas) at the new fee. When it's mined, nonce 41 is used up and the original can never execute. The wallet Cancel button does the same thing.

The same in ethers v6:

import { ethers } from "ethers";

const provider = new ethers.JsonRpcProvider(process.env.RPC_URL);
const wallet = new ethers.Wallet(process.env.PRIVATE_KEY!, provider);

const tx = await wallet.sendTransaction({
  to: wallet.address,
  value: 0n,
  nonce: 41,
  maxFeePerGas: ethers.parseUnits("40", "gwei"),
  maxPriorityFeePerGas: ethers.parseUnits("3", "gwei"),
});
await tx.wait();

Things to know before you click

• It's a race. Replacing doesn't pull the original back. Whichever version gets included first wins, and the other is rejected as "nonce too low". Always check which hash was actually mined.
• Replace the oldest stuck nonce. Replacing nonce 44 does nothing while 41 is stuck.
• If you sent from several tools (wallet, script, another device), make sure they agree on the nonce. Wallets can also show stale nonces; MetaMask lets you set a custom nonce once enabled in its advanced settings.
• You can't cancel a mined transaction. If it's in a block, even a failed one, it's final.
• L2s behave differently. On rollups like Arbitrum, Optimism and Base, a central sequencer orders transactions and there usually isn't a long public mempool wait. A transaction that looks stuck there is more often a nonce problem, an RPC issue or a transaction that was rejected outright.

Avoid it next time

• Use the fee estimates from your provider (provider.getFeeData() in ethers, estimateFeesPerGas in viem), and give maxFeePerGas headroom, often about twice the current base fee. You only pay what's actually needed.
• Don't set a tiny tip to save a little. You'll often pay more to replace it.
• In backends, track your own nonces and monitor pending transactions, then automatically bump fees after a timeout.

Checklist

1. Find the lowest pending nonce for your account; that's the one to fix.
2. Compare the transaction's maxFeePerGas with the current base fee.
3. To speed up, resend with the same nonce and both fee fields raised by more than 10%.
4. To cancel, send 0 ETH to yourself with the same nonce and higher fees.
5. Confirm which hash was mined before doing anything else.

Is ERC-20 approve dangerous? Allowances, permit and infinite approvals

Approve is safe; unlimited, forgotten allowances and unread permit signatures are not. Approve exact amounts, use permit with short deadlines, read every typed-data signature, and revoke old approvals.

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