Handle Refunds & Failures

Refund EVM HTLC

Refund stablecoins locked in an EVM HTLC smart contract when a swap fails or times out.

EVM Refunds: Unlike BTC refunds which the SDK handles, EVM HTLC refunds can be done through the LendaSwap web interface or programmatically using the SDK's getEvmRefundCallData().

When to Refund

Refunds are typically needed when:

You sent stablecoins but didn't receive BTC
The swap timed out (service didn't complete)
The counterparty didn't claim your BTC (for EVM→BTC swaps)
Network issues prevented swap completion

Refund via Web Interface

The easiest way to refund an EVM HTLC is through the LendaSwap web interface:

Go to app.lendaswap.com
Connect your wallet (MetaMask, WalletConnect, etc.)
Navigate to your swap history
Find the expired swap
Click "Refund" button

The web interface handles all the smart contract interaction for you.

Refund with wagmi/viem (React)

import { useWriteContract } from "wagmi";

const refund = await client.getEvmRefundCallData(swapId);

if (!refund.timelockExpired) {
  const expiresIn = refund.timelockExpiry - Math.floor(Date.now() / 1000);
  console.log(`Timelock expires in ${Math.ceil(expiresIn / 60)} minutes`);
} else {
  const { writeContract } = useWriteContract();
  await writeContract({
    address: refund.to as `0x${string}`,
    data: refund.data as `0x${string}`,
  });
}

Refund with ethers.js

import { BrowserProvider } from "ethers";

const provider = new BrowserProvider(window.ethereum);
const signer = await provider.getSigner();

const refund = await client.getEvmRefundCallData(swapId);

if (refund.timelockExpired) {
  const tx = await signer.sendTransaction({
    to: refund.to,
    data: refund.data,
  });
  await tx.wait();
  console.log("Refunded! TX:", tx.hash);
}

Check HTLC Status

Query the smart contract to check refund eligibility:

const refund = await client.getEvmRefundCallData(swapId);

console.log("Timelock expired:", refund.timelockExpired);
console.log("Expiry:", new Date(refund.timelockExpiry * 1000).toISOString());

const swap = await client.getSwap(swapId);
console.log("Swap status:", swap.status);

Important Notes

Gas Fees Required: Unlike claiming via Gelato (which is gasless), refunding an EVM HTLC requires paying gas fees in ETH (Ethereum) or MATIC (Polygon).

Use web interface when possible - It's the simplest approach
Wait for timelock - Refunds are blocked until timelock expires
Gas fees - You need ETH/MATIC for gas to execute the refund
Check both states - Ensure swap isn't already claimed or refunded
Contract address varies - Different HTLC contracts for different networks

Refund Onchain HTLC

Refund funds locked in an onchain Bitcoin HTLC when a swap fails or times out.

Refund Locktime & Conditions

Understanding when and how refunds become available based on locktime expiration.