This guide explains how to use smart wallets from your server to sponsor gas fees for transactions on Ethereum. Using wallets as smart wallets gives your application all the benefits of account abstraction, including gas sponsorship, with the flexibility of wallets. In this setup, an embedded wallet created on your wallet is the signer for the smart wallet. Note that the wallet’s address is not the smart wallet address in this case - it simply authorizes actions taken by the smart wallet. All transactions and assets are tied to the smart wallet. This guide uses Kernel as the smart wallet contract provider, but your implementation can use any smart wallet provider. 0: Install necessary dependencies This guide uses Privy’s server SDK to create the wallet, Pimlico’s `permissionless` package, and `viem`. Install these packages with the following command: ```sh theme={"system"} npm i @privy-io/node permissionless viem ``` 1: Create a wallet Create a `privy` client and use the `create` method from [Privy’s SDK](/wallets/wallets/create/create-a-wallet) to create a wallet. If you already have a wallet you wish to use, you can skip this step. ```ts theme={"system"} import {PrivyClient} from '@privy-io/node'; // Initialize your Privy client const privy = new PrivyClient({ appId: 'your privy app id', appSecret: 'your privy app secret' }); // Create a wallet const { id: walletId, address, chain_type: chainType } = await privy.wallets().create({chain_type: 'ethereum'}); ``` 2: Get a `viem` `LocalAccount` for the wallet Create a viem `LocalAccount` object representing the wallet. Use the `createViemAccount` method from [Privy’s SDK](/wallets/using-wallets/ethereum/web3-integrations#node-js). ```tsx theme={"system"} import {createViemAccount} from '@privy-io/node/viem'; // Create a viem account instance for a wallet const serverWalletAccount = await createViemAccount(privy, { walletId, address }); ``` If your wallet requires an [authorization context](/controls/authorization-keys/using-owners/sign/signing-on-the-server), you should pass it to the `createViemAccount` method like so: ```tsx theme={"system"} const serverWalletAccount = await createViemAccount(privy, { walletId, address, authorizationContext: { authorization_private_keys: ['your authorization private key'] } }); ``` 3: Create a smart wallet Use [`permissionless`](https://docs.pimlico.io/references/permissionless/) to create a smart wallet with the wallet as the signer. Learn more about creating smart wallet accounts in the `permissionless` [docs](https://docs.pimlico.io/references/permissionless/how-to/accounts/use-kernel-account). ```tsx theme={"system"} import {toKernelSmartAccount} from 'permissionless/accounts'; import {entryPoint07Address} from 'viem/account-abstraction'; const kernelSmartAccount = await toKernelSmartAccount({ client: publicClient, entryPoint: { address: entryPoint07Address, version: '0.7' }, owner: serverWalletAccount }); ``` 4: Create a client for the smart wallet You can use this smart wallet client to request signatures and transactions from the smart wallet. Learn more about making transactions on the client in the `permissonless` [docs](https://docs.pimlico.io/references/permissionless/how-to/accounts/use-kernel-account). ```tsx theme={"system"} import {createSmartAccountClient, walletClientToCustomSigner} from 'permissionless'; import {createPublicClient, http} from 'viem'; const bundlerUrl = 'your bundler URL'; const paymasterUrl = 'your paymaster URL'; // Create a viem public client for RPC calls const publicClient = createPublicClient({ chain: sepolia, // Replace this with the chain of your choice transport: http() // Optionally include an RPC override }); // Create the paymaster client to sponsor gas fees on transactions const paymasterClient = createPimlicoClient({ transport: http(paymasterUrl), entryPoint: kernelSmartAccount.entryPoint }); // Create the SmartAccountClient for requesting signatures and transactions (RPCs) const smartAccountClient = createSmartAccountClient({ account: kernelSmartAccount, chain: sepolia, paymaster: paymasterClient, bundlerTransport: http(bundlerUrl), userOperation: { estimateFeesPerGas: async () => (await paymasterClient.getUserOperationGasPrice()).fast } }); ```

Gas management

Documentation Index