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Storing smart account addresses
TIP
Privy now allows you to natively use smart wallet for a better developer experience. Check out the docs here.
Once you've used Privy's embedded wallet as a signer to create smart accounts, you can also store the user's smart account address on their user object.
At a high-level, this is accomplished by requesting a Sign-In With Ethereum (SIWE) signature from the user's smart account, and passing the resulting signature to Privy to verify that the smart account is associated with the authenticated user.
Read below to learn more!
TIP
Storing a user's smart account address on the user object makes the address available in their user
state in your client and the user object you might query from your server. This enables you to easily associate smart account addresses with users.
1. Generate a SIWE message for the smart account
To start, import the useLinkWithSiwe
hook from @privy-io/react-auth
. This hook allows you to generate a SIWE message for an arbitrary wallet and pass the resulting signature for verification.
tsx
import {useLinkWithSiwe} from '@privy-io/react-auth';
Then, call the generateSiweMessage
method returned by the hook to generate a SIWE message for the smart account to sign. As parameters to this method, pass an object with the following fields:
Parameter | Type | Description |
---|---|---|
address | string | Required. The user's smart account address. Must be properly checksummed per EIP-55. |
chainId | number | Required. The chain ID of the smart account. Must be a CAIP-2 formatted chain ID that correspond to a valid network where signatures from the smart account can be verified. |
INFO
Make sure the chainId
you pass to generateSiweMessage
and linkWithSiwe
is CAIP-2 formatted.
As an example, you might generate a SIWE message for the smart account like so:
tsx
const {generateSiweMessage} = useLinkWithSiwe();
const message = await generateSiweMessage({
address: 'insert-smart-account-address',
chainId: 'eip155:8453', // Replace with a CAIP-2 chain ID where signatures from the smart account can be verified
});
2. Request a personal_sign
signature from the smart account
Next, with the message
you generated in step (1), request a EIP191 personal_sign
signature from the smart account.
The interface for requesting this signature may depend on which smart account provider (ZeroDev, Pimlico, Safe, Biconomy, Alchemy) your app uses; see the corresponding guides to understand the best way to request a signature from the wallet.
tsx
// In this example, the `kernelClient` corresponds to a ZeroDev smart account. The interface for requesting
// may depend on your chosen smart account provider, so be sure to swap out this implementation for the
// correct one for your setup.
const signature = await kernelClient.signMessage({
// This `message` is what you generated in step (1)
message: message,
});
3. Pass the signature to Privy
Lastly, pass the signature
from the smart account to Privy using the linkWithSiwe
method returned by the useLinkWithSiwe
hook. As parameters to this method, include an object with the following fields:
Parameter | Type | Description |
---|---|---|
message | string | Required. The SIWE message you generated with generateSiweMessage . |
chainId | number | Required. The CAIP-2 chain ID you passed to generateSiweMessage . |
signature | string | Required. The signature produced by the smart account. |
walletClientType | string | Recommended. A signature indicating the wallet client you'd like to associate with the smart account. We recommend using 'privy_smart_account' . |
connectorType | string | Recommended. A signature indicating the connector type you'd like to associate with the smart account. We recommend using the snake_cased name of your smart account provider, e.g. 'zerodev' . |
As an example, you can pass the smart account's signature to Privy for verification like so:
tsx
const {linkWithSiwe} = useLinkWithSiwe();
await linkWithSiwe({
// The SIWE message generated from `generateSiweMessage`
message: message,
// The same `chainId` you passed to `generateSiweMessage`
chainId: 'eip155:8453',
// The signature from the smart account
signature: signature,
// You can replace this with whatever wallet client you'd like to associate with the smart account
walletClientType: 'privy_smart_account',
// You can replace this with whatever connector type you'd like to associate with the smart account
connectorType: 'zerodev',
});
4. Get the smart account address
Once you've successfully linked the smart account to the user, you can easily get their smart account address from their Privy user
object. Simply inspect the linkedAccounts
array for the entry with:
type: 'wallet'
walletClientType: 'privy_smart_account'
, or any other customwalletClientType
you chose
As an example, you can get the smart account address like so!
tsx
const {user} = usePrivy();
const address = user.linkedAccounts.find(
(account): account is WalletWithMetadata =>
account.type === 'wallet' && account.walletClientType === 'privy_smart_account',
);
That's it! You can also find the user's smart account when querying Privy's API from your server, and applying the same logic to parsing the linked_accounts
array.