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Determine whether vault share approval is needed for a withdrawal operation and prepare the appropriate authorization. This is the recommended entry point for the withdrawal flow. It automatically:
  • Checks existing vault share allowance
  • Detects smart contract wallets (Safe, EIP-4337, EIP-7702)
  • Returns the appropriate authorization result

​
Import

import {
  prepareWithdrawalAuthorization,
  isWithdrawApprovalAuth,
  isWithdrawAlreadyApprovedAuth,
  WithdrawAuthMethod,
} from '@paxoslabs/amplify-sdk'

​
Usage

// First discover the vault
const [vault] = await getVaultsByConfig({
  yieldType: 'CORE',
  chainId: 1,
})

const auth = await prepareWithdrawalAuthorization({
  vaultName: vault.name,
  wantAsset: '0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48', // USDC
  withdrawAmount: '1.0',
  userAddress: '0x1234...',
  chainId: 1,
})

if (isWithdrawApprovalAuth(auth)) {
  // Execute approval transaction
  await walletClient.writeContract(auth.txData)
} else {
  // Already approved, proceed to withdrawal
  console.log(`Allowance: ${auth.allowance}`)
}

​
Parameters

ParameterTypeRequiredDescription
vaultNamestringYesVault name from AmplifyVault.name (e.g. from getVaultsByConfig())
wantAssetAddressYesToken address to receive upon withdrawal
withdrawAmountstringYesVault shares to withdraw (decimal string)
userAddressAddressYesOwner of vault shares
chainIdnumberYesBlockchain network ID
forceMethod"approval" | "allowance_check"NoOverride auto routing behavior

​
Return Type

Returns a discriminated union WithdrawAuthorizationResult:

​
WithdrawAuthMethod.APPROVAL

Returned when approval is needed (insufficient allowance, smart wallet detected in auto mode, or forceMethod: "approval"). 
interface WithdrawApprovalAuthorizationResult {
  method: 'approval'
  txData: ApproveWithdrawOrderTxData // Ready-to-use approval tx
}

​
WithdrawAuthMethod.ALREADY_APPROVED

Returned when existing allowance is sufficient. 
interface WithdrawAlreadyApprovedAuthorizationResult {
  method: 'already_approved'
  allowance: string
  allowanceAsBigInt: string
}

​
Type Guards

Use type guards for type-safe handling: 
import {
  isWithdrawApprovalAuth,
  isWithdrawAlreadyApprovedAuth,
} from "@paxoslabs/amplify-sdk";

const auth = await prepareWithdrawalAuthorization({ ... });

if (isWithdrawApprovalAuth(auth)) {
  // TypeScript knows auth.txData exists
  await walletClient.writeContract(auth.txData);
}

if (isWithdrawAlreadyApprovedAuth(auth)) {
  // TypeScript knows auth.allowance exists
  console.log(auth.allowance);
}
Or use a switch statement: 
switch (auth.method) {
  case WithdrawAuthMethod.APPROVAL:
    await walletClient.writeContract(auth.txData)
    break
  case WithdrawAuthMethod.ALREADY_APPROVED:
    console.log(`Approved: ${auth.allowance}`)
    break
}

​
Smart Wallet Behavior

In auto mode, smart contract wallets (Safe, EIP-4337, EIP-7702) are routed to APPROVAL with approve tx data so they can batch approve + withdraw atomically. 
// Smart wallet detected automatically
const [vault] = await getVaultsByConfig({ yieldType: 'CORE', chainId: 1 })

const auth = await prepareWithdrawalAuthorization({
  vaultName: vault.name,
  wantAsset: USDC_ADDRESS,
  withdrawAmount: '1.0',
  userAddress: safeAddress, // Smart contract wallet
  chainId: 1,
})

// Returns APPROVAL in auto mode for smart wallets
// auth.method === WithdrawAuthMethod.APPROVAL
The SDK detects smart wallets by checking for deployed bytecode at the address using getCode. This covers:
  • Safe (Gnosis Safe) multi-sig wallets
  • EIP-4337 smart accounts (e.g., Biconomy, ZeroDev, Alchemy)
  • EIP-7702 delegated EOAs
  • Privy embedded wallets (when using smart wallets)

​
Force Method Overrides

Use forceMethod for deterministic behavior: 
const [vault] = await getVaultsByConfig({ yieldType: 'CORE', chainId: 1 })

// Always return approval tx data (skip checks)
const forceApproval = await prepareWithdrawalAuthorization({
  vaultName: vault.name,
  wantAsset: USDC_ADDRESS,
  withdrawAmount: '1.0',
  userAddress,
  chainId: 1,
  forceMethod: 'approval',
})

// Always run allowance check (skip smart-wallet heuristic)
const forceAllowanceCheck = await prepareWithdrawalAuthorization({
  vaultName: vault.name,
  wantAsset: USDC_ADDRESS,
  withdrawAmount: '1.0',
  userAddress,
  chainId: 1,
  forceMethod: 'allowance_check',
})

​
Examples

import {
  getVaultsByConfig,
  prepareWithdrawalAuthorization,
  isWithdrawApprovalAuth,
  prepareWithdrawal,
  YieldType,
} from "@paxoslabs/amplify-sdk";

async function withdraw(
  walletClient: WalletClient,
  publicClient: PublicClient,
  userAddress: `0x${string}`,
) {
  const USDC = "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48";
  const withdrawAmount = "1.0";

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

  // Step 1: Authorize
  const auth = await prepareWithdrawalAuthorization({
    vaultName: vault.name,
    wantAsset: USDC,
    withdrawAmount,
    userAddress,
    chainId: 1,
  });

  if (isWithdrawApprovalAuth(auth)) {
    const approveHash = await walletClient.writeContract(auth.txData);
    await publicClient.waitForTransactionReceipt({ hash: approveHash });
  }

  // Step 2: Submit withdrawal order
  const withdrawTx = await prepareWithdrawal({
    vaultName: vault.name,
    wantAsset: USDC,
    userAddress,
    chainId: 1,
    withdrawAmount,
  });

  const hash = await walletClient.writeContract(withdrawTx);
  return hash;
}

​
Comparison with Deposit Authorization

prepareWithdrawalAuthorization() mirrors the deposit flow’s prepareDepositAuthorization():
FeatureDeposit AuthWithdrawal Auth
MethodsPERMIT, APPROVAL, ALREADY_APPROVEDAPPROVAL, ALREADY_APPROVED
Permit SupportYes (EIP-2612)No
Smart Wallet Auto-DetectYesYes
Force MethodforceMethod: "permit" | "approval"forceMethod: "approval" | "allowance_check"
Withdrawals don’t support EIP-2612 permits since the approval is on vault shares (BoringVault ERC20), not the deposit token.

​
Error Handling

ErrorDescriptionResolution
Vault not foundInvalid vault nameVerify vault name via getVaultsByConfig()
Failed to check withdrawal approvalOn-chain multicall failedCheck RPC connectivity and retry
import {
  getVaultsByConfig,
  prepareWithdrawalAuthorization,
  APIError,
} from '@paxoslabs/amplify-sdk'

const [vault] = await getVaultsByConfig({ yieldType: 'CORE', chainId: 1 })

try {
  const auth = await prepareWithdrawalAuthorization({
    vaultName: vault.name,
    wantAsset: USDC_ADDRESS,
    withdrawAmount: '1.0',
    userAddress: '0x...',
    chainId: 1,
  })
} catch (error) {
  if (error instanceof APIError) {
    console.error('SDK Error:', error.message)
  }
}