Smart server wallets are the recommended way to perform blockchain operations with Engine. Each smart server wallet consists of an EOA (managed internally by Engine) and a smart account (using thirdweb's default account implementation).

Smart server wallets inherit smart account benefits and offer several advantages over traditional EOAs:

• Gas Management: Built-in paymaster eliminates the need to maintain gas tokens. This means you never need to hold crypto or top up gas.
• Better Nonce Management: Smart accounts use multi-dimensional nonces, which are more efficient than EOAs.
• Simple Integration: Works with all existing Engine endpoints without any code changes.

The smart account is automatically deployed the first time you send a transaction on a chain. You don't need to think about deploying or managing the smart account - Engine handles everything behind the scenes. All transactions are sent as UserOperations to the EntryPoint contract on chain.

Smart server wallets have no additional costs to use with your Engine instance. Transactions sent from smart backend wallets follow the same billing model as regular account abstraction transactions with thirdweb. Smart accounts need to be deployed on each chain. This costs gas and is billed to your account like any other transaction.