How to Handle a Pending or Failed Swap

A pending or failed swap is an Ethereum transaction that has not completed or has reverted; first check its on-chain status, then decide whether to wait, replace it or fix the cause before retrying. The key distinction is whether the transaction is still waiting to be included in a block or has already been confirmed as failed.

Fermi swap is a decentralized way to exchange tokens from your wallet. If you are choosing among trade types, how Fermi swap handles trade types covers when each one fits; this article focuses on what to do after a transaction stalls or fails.

Find the transaction before changing anything

A pending label in a swap service is not enough to tell you what happened; look for the transaction hash in your wallet’s activity and check that hash on Etherscan. Confirm that you are viewing Ethereum and that the sender address matches your wallet. If there is no hash, the transaction may not have been broadcast, so check the wallet’s pending signature or error before submitting another swap.

Once broadcast, an Ethereum transaction enters a pool of transactions waiting for validators to include them in a block. Each transaction from an account has a sequential nonce, a number that marks its place in that account’s transaction order. If an earlier nonce is stuck, later transactions from the same account usually wait behind it, even if they are swaps with better fees.

On Etherscan, check whether the transaction is pending, successful or failed, and note its nonce. If you see a confirmed failure, skip the speed-up steps: the transaction has already been processed. If Etherscan shows success but the swap service still says pending, the chain has finished the transaction and the service’s display may simply be behind.

A pending transaction may need time or a replacement

A pending transaction often needs time when its fee offer is too low for current demand. Ethereum transactions include a priority fee, offered to the validator, and a maximum fee cap; if those settings no longer compete with transactions entering blocks, yours can wait in the pool. The fee market changes with network activity, so a fee that worked moments ago may now be too low.

For a typical case, imagine a swap stuck behind another transaction from the same wallet. Check the older transaction first: speeding up the later swap will not clear the queue if the earlier nonce is still waiting. If you decide to replace a pending transaction, act on the original nonce in your wallet.

1. Open the pending transaction in your wallet and check its nonce against the pending transactions listed for that account.
2. If you still want the transaction, choose the wallet’s speed-up option and review the new fee before signing; it should increase the fee offer enough to compete with current conditions.
3. If you want to abandon it, use the wallet’s cancel option, which usually sends a replacement with the same nonce and no token swap. Review the recipient and amount before signing.
4. Wait for either the original transaction or its replacement to confirm, then check the nonce and status again before starting another swap.

A replacement competes with the original because both use the same nonce; only one can be confirmed in that position. The wallet or node may require a minimum fee increase, and the original could still win the race. Until one confirms, avoid repeatedly signing new swaps: they can queue behind the unresolved transaction.

A confirmed failure needs a cause check

A failed transaction has been included in a block, but its contract call reverted. The swap did not complete, yet the transaction still used network resources, so you still pay gas. For example, if a failed transaction used 120,000 gas at an effective price of 25 gwei, the gas cost is 0.003 ETH. That is an illustration; the actual amount depends on gas used and the price shown in the transaction receipt.

Read the wallet error or explorer details before retrying. Common causes include:

• Slippage: the token price moved beyond the swap’s allowed tolerance before execution.
• Insufficient balance: the wallet lacked enough of the input token or ETH for gas.
• Allowance: the contract did not have permission to use the required token amount.
• Execution conditions: the quote expired or the trade could not be filled at execution.

For a failed swap, first confirm that the receipt says failed and that your token balances have not changed from the attempted trade. Then correct the cause: add enough ETH for gas, approve the required token if prompted, or request a fresh quote if price movement or expiry caused the revert. A retry is a new transaction with a new nonce and its own gas cost.

Check the receipt before trying again

A successful receipt means the transaction executed, even if a wallet balance or swap page has not refreshed yet. Check the receipt and token transfers on Etherscan, then refresh the wallet or give its balance display time to update. This edge case matters because sending a second swap after the first one succeeded can trade more than you intended.

Before signing any replacement or retry, verify the network and token addresses shown by your wallet. If the transaction is still pending, resolve its nonce first; if it failed, fix the reported cause; if it succeeded, confirm the resulting token balance before taking another action.