signConfirmDelivery - Palindrome Crypto Pay SDK Documentation

async signConfirmDelivery(
  walletClient: WalletClient,
  escrowId: bigint,
  deadline: bigint,
  nonce: bigint
): Promise<Hex>

Signs an EIP-712 typed message for gasless confirm delivery. The buyer signs off-chain, and anyone can submit the signature on-chain to release funds.

Parameters

walletClient: WalletClient – Buyer's connected wallet
escrowId: bigint – The escrow ID
deadline: bigint – Unix timestamp when signature expires
nonce: bigint – User's nonce (from getUserNonce())

Returns

Promise<Hex> – 65-byte EIP-712 signature

import { createPalindromeSDK } from '@/lib/createSDK';

const { sdk, walletClient } = await connectAndInitSDK(); // buyer

const escrowId = 42n;

try {
  // Step 1: Get nonce and create deadline
  const nonce = await sdk.getUserNonce(escrowId, walletClient.account.address);
  const deadline = await sdk.createSignatureDeadline(60); // 60 minutes

  // Step 2: Sign the confirm delivery message
  const signature = await sdk.signConfirmDelivery(
    walletClient,
    escrowId,
    deadline,
    nonce
  );

  console.log("Signature:", signature);
  console.log("Deadline:", new Date(Number(deadline) * 1000));
  console.log("Nonce:", nonce);

  // Step 3: Send to relayer or submit yourself
  // ...

} catch (error: any) {
  console.error("Signing failed:", error.message);
}

Signature Structure (EIP-712)

// Domain
{
  name: "PalindromeCryptoEscrow",
  version: "1",
  chainId: 84532,  // Base Sepolia
  verifyingContract: contractAddress
}

// Types
{
  ConfirmDelivery: [
    { name: "escrowId", type: "uint256" },
    { name: "buyer", type: "address" },
    { name: "seller", type: "address" },
    { name: "arbiter", type: "address" },
    { name: "token", type: "address" },
    { name: "amount", type: "uint256" },
    { name: "depositTime", type: "uint256" },
    { name: "deadline", type: "uint256" },
    { name: "nonce", type: "uint256" }
  ]
}

Full Gasless Flow

// 1. Buyer signs (no gas)
const nonce = await sdk.getUserNonce(escrowId, buyerAddress);
const deadline = await sdk.createSignatureDeadline(60);
const coordSig = await sdk.signConfirmDelivery(walletClient, escrowId, deadline, nonce);
const walletSig = await sdk.signWalletAuthorization(walletClient, escrowWallet, escrowId);

// 2. Send signatures to backend
await sendToRelayer({ escrowId, coordSig, walletSig, deadline, nonce });

// 3. Relayer submits on-chain
await sdk.confirmDeliverySigned(relayerWallet, escrowId, coordSig, deadline, nonce, walletSig);