Announcing Gasless Approvals on CoW Swap

The CoW Swap team is excited to release a simpler trading experience for its users. Gasless approvals allow traders to swap over 150 tokens completely gaslessly through CoW Swap.

Before the launch of gasless approvals, CoW Swap users benefitted from gasless trading thanks to CoW Swap’s intent-based execution model. However, they still needed to pay gas fees (in ETH) to execute approval transactions the first time they wanted to trade any token.

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!

Benefits of gasless approvals

This new upgrade comes with a host of benefits relevant to EOA and multisig wallets alike.

• 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
• 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
• Bundling efficiency: Approval transactions execute alongside orders, in the same block — shielded from fluctuating gas prices, for a more cost-efficient experience overall
• 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

Gasless approvals under the hood

Gasless approvals rely on ERC-2612: Permit Extension for EIP-20 Signed Approvals.

Essentially, a function 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. For security, gasless approvals rely on nonces which indicate the number of times a permit signature has been used. (There is also a time window in which the signature must be used.) This protects users from replay attacks because it is impossible to replicate an approval with the same nonce.

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.

Now live on CoW Swap

Gasless approvals are now live on CoW Swap for Ethereum Mainnet. See which tokens are currently supported by checking out the CoW Swap Permittable Tokens List.

As always, on CoW Swap:

• Orders are free to place and cancel
• Traders never pay for failed transactions
• Fees that cover settlement costs are paid in traders’ sell tokens
• Traders are fully protected from MEV

Happy trading!