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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

const auth = await prepareWithdrawalAuthorization({
  yieldType: "CORE",
  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
yieldTypeYieldTypeYesYield strategy (CORE, TREASURY, FRONTIER)
wantAssetAddressYesToken address to receive upon withdrawal
withdrawAmountstringYesVault shares to withdraw (decimal string)
userAddressAddressYesOwner of vault shares
chainIdChainIdYesBlockchain 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 auth = await prepareWithdrawalAuthorization({
  yieldType: "CORE",
  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: 
// Always return approval tx data (skip checks)
const forceApproval = await prepareWithdrawalAuthorization({
  yieldType: "CORE",
  wantAsset: USDC_ADDRESS,
  withdrawAmount: "1.0",
  userAddress,
  chainId: 1,
  forceMethod: "approval",
});

// Always run allowance check (skip smart-wallet heuristic)
const forceAllowanceCheck = await prepareWithdrawalAuthorization({
  yieldType: "CORE",
  wantAsset: USDC_ADDRESS,
  withdrawAmount: "1.0",
  userAddress,
  chainId: 1,
  forceMethod: "allowance_check",
});

​
Examples

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

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

  // Step 1: Authorize
  const auth = await prepareWithdrawalAuthorization({
    yieldType: "CORE",
    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({
    yieldType: "CORE",
    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
No vault found for assetInvalid yield type, chain, or asset combinationVerify parameters match an existing vault
Failed to check withdrawal approvalOn-chain multicall failedCheck RPC connectivity and retry
import { prepareWithdrawalAuthorization, APIError } from "@paxoslabs/amplify-sdk";

try {
  const auth = await prepareWithdrawalAuthorization({
    yieldType: "CORE",
    wantAsset: USDC_ADDRESS,
    withdrawAmount: "1.0",
    userAddress: "0x...",
    chainId: 1,
  });
} catch (error) {
  if (error instanceof APIError) {
    console.error("SDK Error:", error.message);
  }
}