This article focuses on using the Casa ETH Pay Wallet as your ethereum relay, and the fees associated with it.
What is a relay?
An ethereum relay is a way to manage interactions with ethereum smart contracts. Casa customers may use Casa, or they may use their ETH Pay Wallet (a separate "single signature" wallet), as a relay for their multi-key vault.
For more information on these two relay types in the Casa app, see Relay types for ethereum vaults.
How does it work?
If a member has opted to use the ETH Pay Wallet Relay (rather than the Casa Relay), the ETH Pay Wallet will relay transactions and other activity from the vault.
For instance, when a user sends an ETH transaction from their vault, or takes other actions in their vault such as replacing a key, their ETH Pay Wallet will automatically get a reimbursement by the vault for the gas fees (note that this reimbursement does not occur during the vault creation, only for transactions made after vault creation).
In practice, this means that when you send ETH from your Casa vault, a little bit of extra ETH is sent to the ETH Pay Wallet. The ETH Pay Wallet, being the relay that you selected, pays the Network fees on behalf of your vault, using the funds that were sent from the vault.
Note that the estimated fee that's sent to your Pay Wallet is just that - an estimate. The actual amount that is paid for the transaction will depend on the current state and activity of the ethereum network, and will rarely be the exact amount of the estimate. The actual amount paid for the transaction may be higher or lower than the estimate (This is displayed in your transaction history as the Net Fee).
We'll use the following example of how fees may be paid by a Casa customer using their ETH Pay Wallet as a relay.
- A transaction for $100 worth of ETH to an external address is created from a Casa multi-key vault.
- Based on current network activity, Casa app estimates that the cost of the fee for the ethereum network will be $5.
- The vault in Casa app pays the $5 worth of ETH to the ETH Pay Wallet in the Casa app
- The transaction is successful, but the actual cost was only $4.
- The Pay Wallet is left with $1 added to the wallet balance
For any additional questions about the ETH Pay Relay, how transaction fees work, or anything else, feel free to reach out.