How to: Gasless swaps on Ethereum
Gas fees are an integral part of the blockchain ecosystem. At their simplest, they are the fees a user pays to validate transactions. That fee goes to either a miner or validator to help process transactions in a block. The price of gas on networks can vary widely.
That’s why in this article we’re going to explain that thanks to CoW Swap, you can perform gasless swaps on Ethereum in a few simple steps.
The burden of gas fees in crypto trading
On Ethereum, gas is required for you to perform most actions. From the buying and selling of cryptocurrencies, to trading NFTs, to staking, most actions will typically require you to pay a gas fee.
However, because of the fluctuating nature of gas fees, for many traders, maintaining enough ethereum to pay gas fees on trades can sometimes mean you miss out on making trades at the optimal moment.
On Ethereum, gas is required for you to perform most actions. From the buying and selling of cryptocurrencies, to trading NFTs, to staking, most actions will typically require you to pay a gas fee.
However, because of the fluctuating nature of gas fees, for many traders, maintaining enough ethereum to pay gas fees on trades can sometimes mean you miss out on making trades at the optimal moment.
This is because if you do not have enough Ethereum to pay your gas fee, the transaction will not complete. Or, if your trading requires you to execute your trade quickly, during busy times you may have to pay considerably more to ensure your trade can complete in time. The below chart demonstrates the fluctuating nature of gas fees over the last five years.
The amount of gas you pay, especially during busy times, can add up. There are countless examples of the high gas fees users have paid to transact on Ethereum. Last year, one user paid $700,000 for a single Ethereum transaction. Other famous examples included a $23.5 million fee to move just 100,000 in Tether, and another user paid $108,000 paid for a single transaction in late 2024. It’s not Ethereum traders feeling the gas fee pinch.
Over on Bitcoin, one user paid $3.1 million in transaction fees, demonstrating that trading during busy times can be prohibitively expensive. But there are ways you can avoid getting caught out by gas fees, as we’ll explore below.
What are gasless approvals?
Gasless approvals, or meta transactions as they are sometimes referred to, means that a third-party, called a relayer, or on CoW Swap, a solver, can send another user’s transaction on their behalf, covering the cost of gas in the process.
In a normal transaction, when you want to trade, you sign a transaction that is then added to the upcoming block in what is called the mempool. To find out more about mempools, and some of the risks that come with it, check our guide to MEV on Ethereum.
Digging a bit deeper, a user ‘signs’ a message that contains an intent to trade, along with the details of the type of trade and what token they want to transact in.
The solver is then responsible for paying the gas fee. How does this all work? Gasless approvals rely on ERC-2612: Permit Extension for EIP-20 Signed Approvals. This upgrade to how Ethereum works creates a signature that can call approvals directly on behalf of the owner.
This allows a third party, such as a solver, to spend funds on behalf of the user.
Each Ethereum transaction has a minimum fixed transaction cost associated with it. When executing transactions individually, this cost is usually higher per action than if users bundle multiple transactions together. So, in addition to creating a better user experience for traders, gasless approvals also lower the overall cost of trading on CoW Swap.
With gasless approvals, CoW Swap now allows users to sign a message (gas free!) that gives solvers permission to execute the approval transaction on their behalf. Solvers then bundle the approval transaction with the first swap, and users pay fees in the sell token.
The result? Users can now do an entire swap, even for a new token, without spending a gwei in ETH, or even holding any ETH in their wallet at all. That’s a smoooooother (and cheaper) user experience. Moo-gnificent!
All of this means that for end users, there are lower fees, a more streamlined process and better security. We go into more detail on the benefits in the next section.
Why gasless swaps are a game changer for Ethereum
Gasless swaps on Ethereum means that traders can execute their trades without having to worry and factor in volatile gas prices. There are a range of other benefits, too.
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Fully ETH-less swaps: New users and fresh wallets can complete swaps end-to-end without needing ETH — that’s especially nice for airdrop farmers and privacy seekers.
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Faster trades: CoW Swap users don’t have to wait for an approval transaction to execute before the swap — traders can now swap right away, even with tokens they haven’t traded before.
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Bundling efficiency: Approval transactions execute alongside orders, in the same block — shielded from fluctuating gas prices, for a more cost-efficient experience overall.
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Enhanced security: Only an approved spender can execute transactions on behalf of a trader — users can trust that CoW Swap is as secure as ever.
Ready to execute your first gasless swap? We will tell you how in the next section.
How to execute gasless swaps on Ethereum using CoW Swap
Step 1: Connect your wallet
Navigate to the swap.cow.fi. Once you’re there, you’ll need to connect your wallet to the swap interface.
In the top right hand corner of your screen, you’ll find a “connect wallet” button. Click that and an interface will pop up.
Select the wallet of your choice and follow the instructions from your wallet provider.
Step 2: Select your trading pair
Once you're all connected and ready to go, select the trading pair you would like to share. You can pick from the drop down menus on the right hand side, as you can see below.
Once you’ve picked the one you want, enter the amount you want to swap. Once selected CoW Swap does its magic, working out the best price available to you.
Step 3: Initiate the Swap with gasless approval
CoW Swap has gasless trading on more than 150 token pairs. To find out if your token pair can be gasless, CoW Swap will highlight if it is, as it appears below.
Step 4: Confirm and monitor your transaction
Ready to confirm? Hit the trade button and let CoW Swap’s solver network do the rest, via CoW Swap’s Order Flow Auctions. This is a process where solvers compete to fulfil trades. The aim is to ensure users capture as much value from each swap or trade, while also being protected from Maximal Extractable Value (MEV).
The key point to take away from OFA is that it’s a competitive bidding system where solvers compete over who can make the best offer, which is then selected by the protocol. This system not only simplifies the trading process but also ensures traders access the best available price without the need to manually search through multiple platforms.
So not only are you able to trade gaslessly, CoW Protocol’s solver network competes to give you the best deal possible.
Next Steps
Curious about gasless swaps on Ethereum? We have plenty of resources you can use to understand the concept more fully. Here are a few more resources to get started:
Ready to trade without paying gas? Head to CoW Swap to start trading.
FAQs about gasless swap on Ethereum
What is the core concept behind gasless swaps?
Gasless swaps allow users to execute transactions without directly paying the associated gas fees in the native currency being purchased. Instead, a third party, often called a relayer or solver, covers the gas costs on behalf of the user. This process typically involves the user signing a message that expresses their intent to trade, rather than signing a traditional blockchain transaction. The third-party then bundles the transactions and swaps, and users pay fees in the sell token, instead of in the native currency.
How do gasless swaps enhance the user experience for Ethereum traders?
Gasless swaps significantly improve the trading experience by eliminating the need for users to hold the native currency. This enables smoother, uninterrupted trading, especially for new users or those with fresh wallets. Additionally, by bundling approval transactions with swaps, they offer faster execution and protect users from the volatility of gas prices. This makes trading more accessible, secure, and efficient.
What role do solvers play in facilitating gasless transactions?
Solvers (sometimes known as relayers) are crucial third parties in the gasless swap mechanism, especially on platforms like CoW Swap. They are responsible for paying the gas fees required to process a user's transaction. Solvers receive a user's signed intent to trade and then execute the transaction on-chain, often bundling approval steps with the main swap. This system allows users to complete entire swaps without directly interacting with gas fees.
Do gasless swaps eliminate all costs for the user?
While gasless swaps remove the direct burden of paying volatile gas fees with ETH, they do not necessarily make transactions entirely free. The cost of the gas is typically absorbed by the relayer or solver, who then factors this cost into the overall trade price or is reimbursed through the tokens being swapped. This abstraction means users avoid gas management but still contribute to the operational costs indirectly.
How do gasless swaps offer protection against MEV and other trading risks?
Gasless swaps, particularly those processed through mechanisms like CoW Protocol’s Order Flow Auctions, can significantly protect users from Maximal Extractable Value (MEV) and other trading risks. Solvers compete to fulfill trades, often matching orders peer-to-peer or using private market makers, which helps shield transactions from public mempools where MEV bots operate. This competitive process ensures users receive optimal pricing while minimizing the risk of front-running or sandwich attacks.
