prepareDepositPermitSignature

Builds the EIP-712 typed data needed to sign a permit for a deposit. Returns structured data ready to pass to signTypedData or eth_signTypedData_v4.

In most cases you should use prepareDepositAuthorization() which calls this function internally and returns the permit data as part of its result. Use prepareDepositPermitSignature directly when you need fine-grained control over the permit parameters, or need to pre-fetch token metadata to avoid extra RPC calls.

Import

import { prepareDepositPermitSignature } from "@paxoslabs/amplify-sdk";

Usage

const [vault] = await getVaultsByConfig({
  yieldType: YieldType.CORE,
  chainId: 1,
  depositAssetAddress: "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
});

const permitData = await prepareDepositPermitSignature({
  vaultName: vault.name,
  depositAsset: "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
  depositAmount: "1000",
  to: userAddress,
  chainId: 1,
});

// Sign with wallet
const signature = await walletClient.signTypedData({
  account: userAddress,
  ...permitData,
});

Parameters

Parameter	Type	Required	Description
`vaultName`	`string`	Yes	Account name from `AmplifyVault.name`
`depositAsset`	`Address`	Yes	Token contract address
`depositAmount`	`string`	Yes	Amount to deposit as decimal string (e.g., `"100.25"`)
`to`	`Address`	Yes	Recipient address for account shares
`chainId`	`number`	Yes	Blockchain network ID
`deadline`	`bigint`	No	Permit deadline in seconds (default: 1 hour from now)
`nonce`	`bigint`	No	Token permit nonce (fetched on-chain if omitted)
`decimals`	`number`	No	Token decimals (fetched on-chain if omitted)
`tokenName`	`string`	No	EIP-712 domain token name (fetched on-chain if omitted)
`tokenVersion`	`string`	No	EIP-712 domain token version (fetched on-chain if omitted)

interface PrepareDepositPermitSignatureParams {
  /** Vault name (from AmplifyVault.name) */
  vaultName: string;
  /** Token contract address */
  depositAsset: Address;
  /** Amount to deposit as decimal string */
  depositAmount: string;
  /** Recipient address for vault shares */
  to: Address;
  /** Blockchain network ID */
  chainId: number;
  /** Permit deadline in seconds (default: now + 3600) */
  deadline?: bigint;
  /** Pre-fetched token nonce (skips on-chain call) */
  nonce?: bigint;
  /** Pre-fetched token decimals (skips on-chain call) */
  decimals?: number;
  /** Pre-fetched EIP-712 token name (skips on-chain call) */
  tokenName?: string;
  /** Pre-fetched EIP-712 token version (skips on-chain call) */
  tokenVersion?: string;
}

The optional nonce, decimals, tokenName, and tokenVersion parameters are performance optimizations. When provided, they skip the corresponding on-chain multicall reads, reducing latency in applications that already have this token metadata.

Return Type

interface PermitSignatureData {
  /** User's wallet address (permit signer) */
  account: Address;
  /** EIP-712 domain */
  domain: EIP712Domain;
  /** EIP-712 types */
  types: typeof PERMIT_TYPES;
  /** Permit message */
  message: {
    owner: Address;
    spender: Address;
    value: bigint;
    nonce: bigint;
    deadline: bigint;
  };
  /** Primary type */
  primaryType: "Permit";
}

The returned object is directly compatible with viem’s signTypedData, wagmi’s useSignTypedData, and eth_signTypedData_v4. The account field is the user address passed as the to parameter.

Examples

Viem — direct signing
Privy — eth_signTypedData_v4
With pre-fetched metadata

import { createWalletClient, custom } from "viem";
import { mainnet } from "viem/chains";
import {
  getVaultsByConfig,
  prepareDepositPermitSignature,
  prepareDepositWithPermitTxData,
  YieldType,
} from "@paxoslabs/amplify-sdk";

const walletClient = createWalletClient({
  account,
  chain: mainnet,
  transport: custom(window.ethereum),
});

const USDC = "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48" as const;

const [vault] = await getVaultsByConfig({
  yieldType: YieldType.CORE,
  chainId: mainnet.id,
  depositAssetAddress: USDC,
});

// Build permit data
const permitData = await prepareDepositPermitSignature({
  vaultName: vault.name,
  depositAsset: USDC,
  depositAmount: "1000",
  to: account,
  chainId: mainnet.id,
});

// Sign
const signature = await walletClient.signTypedData({
  account,
  ...permitData,
});

// Build deposit tx
const txData = await prepareDepositWithPermitTxData({
  vaultName: vault.name,
  depositAsset: USDC,
  depositAmount: "1000",
  to: account,
  chainId: mainnet.id,
  signature,
  deadline: permitData.message.deadline,
});

await walletClient.writeContract({
  address: txData.address,
  abi: txData.data.abi,
  functionName: txData.data.functionName,
  args: txData.data.args,
  account,
});

import { useWallets } from "@privy-io/react-auth";
import {
  getVaultsByConfig,
  prepareDepositPermitSignature,
  prepareDepositWithPermitTxData,
  toEthSignTypedDataV4,
  YieldType,
} from "@paxoslabs/amplify-sdk";

const { wallets } = useWallets();
const wallet = wallets[0];
const owner = wallet.address as `0x${string}`;

const USDC = "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48" as const;

const [vault] = await getVaultsByConfig({
  yieldType: YieldType.CORE,
  chainId: 1,
  depositAssetAddress: USDC,
});

const permitData = await prepareDepositPermitSignature({
  vaultName: vault.name,
  depositAsset: USDC,
  depositAmount: "1000",
  to: owner,
  chainId: 1,
});

// Use toEthSignTypedDataV4 to serialize for eth_signTypedData_v4
const provider = await wallet.getEthereumProvider();
const signature = await provider.request({
  method: "eth_signTypedData_v4",
  params: [owner, toEthSignTypedDataV4(permitData)],
}) as `0x${string}`;

const txData = await prepareDepositWithPermitTxData({
  vaultName: vault.name,
  depositAsset: USDC,
  depositAmount: "1000",
  to: owner,
  chainId: 1,
  signature,
  deadline: permitData.message.deadline,
});

// If you already have token metadata, pass it to avoid extra RPC calls
const permitData = await prepareDepositPermitSignature({
  vaultName: vault.name,
  depositAsset: USDC,
  depositAmount: "1000",
  to: userAddress,
  chainId: 1,
  // Pre-fetched values skip on-chain reads
  nonce: 5n,
  decimals: 6,
  tokenName: "USD Coin",
  tokenVersion: "2",
});

Helper: `toEthSignTypedDataV4`

import { toEthSignTypedDataV4 } from "@paxoslabs/amplify-sdk";

Converts PermitSignatureData to a JSON string format compatible with eth_signTypedData_v4 (adds the EIP712Domain type entry and serializes bigints as strings):

const jsonStr = toEthSignTypedDataV4(permitData);

const signature = await provider.request({
  method: "eth_signTypedData_v4",
  params: [address, jsonStr],
});

Helper: `parsePermitSignature`

import { parsePermitSignature } from "@paxoslabs/amplify-sdk";

Splits a hex permit signature into its v, r, s components:

const { v, r, s } = parsePermitSignature("0xabc...def");

Handles both legacy v-based and modern yParity-based signature formats.

Error Handling

Error Message Pattern	Description	Resolution
`"SDK not initialized"`	SDK used before init	Call `initAmplifySDK()` first
`"Vault not found"`	No account matches `vaultName`	Verify account name via `getVaultsByConfig()`
`"Token does not support permits"`	Token not on permit allowlist	Use approval flow

Deposit Workflow - Unified API (recommended)
prepareDepositWithPermitTxData - Build deposit tx after signing
getVaultsByConfig - Discover account names

Getting started

Amplify

USDG0

prepareDepositPermitSignature

Import

Usage

Parameters

Return Type

Examples

Helper: `toEthSignTypedDataV4`

Helper: `parsePermitSignature`

Error Handling

​Import

​Usage

​Parameters

​Return Type

​Examples

​Helper: toEthSignTypedDataV4

​Helper: parsePermitSignature

​Error Handling

​Related

Import

Usage

Parameters

Return Type

Examples

Helper: `toEthSignTypedDataV4`

Helper: `parsePermitSignature`

Error Handling

Related