HTLC settlements

Cancelling an HTLC settlement stops the exchange and refunds escrowed local assets to the senders that locked them. While the settlement is pending, one local participant can cancel it. Once every local sender approves, each local participant must cast a cancel vote.

Use this page when you need to stop an HTLC settlement before execution. If the cutoff date has already passed, use Withdraw expired instead.

Before you cancel

Check the settlement state before you choose what to do:

The contract treats local participants as the unique local sender and recipient addresses in the settlement flows. A sender who is also a recipient counts once. Users outside the local flows cannot cancel the settlement or vote to cancel it.

Cancel before the settlement has all approvals

When an HTLC settlement does not yet have every local sender approval, any local participant can stop it without collecting votes from the others.

Propose cancellation on an armed settlement

An armed HTLC settlement has every required local sender approval. At that point, DALP requires unanimous votes from the local participants before refunding escrow. This prevents one participant from cancelling after the other side has already coordinated external chain commitments.

Withdraw your cancel vote

A local participant can withdraw their own cancel vote while the armed settlement is still open and the final required vote has not been cast. Use this only when the settlement should remain armed.

1. Open the armed settlement.
2. Click Withdraw Cancel Proposal.
3. Submit the wallet verification.

DALP removes the vote. The settlement remains armed and cannot cancel until the participant proposes cancellation again.

You cannot withdraw a cancel vote after the settlement has cancelled, executed, expired, or after the HTLC secret is published.

What cancellation changes

• DALP clears active cancel votes when the settlement cancels.
• DALP returns escrowed local assets to the sender addresses that locked them.
• DALP marks the settlement as Cancelled. The settlement cannot execute after that.
• DALP blocks cancel and withdraw-cancel requests once the HTLC secret is published.

API behavior

The public cancel endpoint queues a transaction against the settlement contract. The endpoint accepts the settlement address and wallet verification, then returns the result. Request and response shapes are below.

POST /api/v2/addons/xvp-cancellation-requests
Content-Type: application/json

{
  "settlementAddress": "0x...",
  "walletVerification": {
    "secretVerificationCode": "123456",
    "verificationType": "PINCODE"
  }
}

When the platform processes the request synchronously, it returns the contract output in the standard blockchain mutation envelope.

{
  "data": {
    "transactionHash": "0x..."
  },
  "meta": {
    "txHashes": ["0x..."]
  },
  "links": {
    "self": "/v2/addons/xvp-cancellation-requests"
  }
}

If you send Prefer: respond-async, the platform accepts the request for asynchronous processing and gives you a transaction status URL instead:

{
  "transactionId": "018f2f6e-7c6a-7c64-9a5a-4f5e6a3c2b10",
  "status": "QUEUED",
  "statusUrl": "/api/v2/transaction-requests/018f2f6e-7c6a-7c64-9a5a-4f5e6a3c2b10"
}

For pending settlements, the contract cancels immediately. For armed HTLC settlements, the same cancel request records the caller's cancel vote. A second cancel request from the same participant while that vote is still active is not a safe retry. Verify the settlement state before retrying a submitted request.

Use withdraw-cancel only when the participant intentionally wants to remove an active cancel vote before the final required vote is cast.

Production checks

Before cancelling an HTLC settlement, confirm the following points.

Troubleshooting

Next steps