Withdraw to Lightning

Pay any Lightning invoice directly from your Spark wallet.

Lightning Withdrawal Flow

The complete process for withdrawing Bitcoin from Spark to the Lightning Network:

Get Lightning Invoice

Obtain a Lightning invoice from the recipient or Lightning service.

// Example Lightning invoice
const invoice = "lnbcrt1u1pnm7ammpp4v84f05tl0kzt6g95g056athdpp8f8azvg6d7epz74z562ymer9jqsp5nc50gazvp0e98u42jlu653rw0eutcl067nqq924hf89q4la4kd9sxq9z0rgqnp4qdnmwu8v22cvq9xsv2l05cn9rre7xlcgdtntxawf8m0zxq3qemgzqrzjqtr2vd60g57hu63rdqk87u3clac6jlfhej4kldrrjvfcw3mphcw8sqqqqrj0q7ew45qqqqqqqqqqqqqq9qcqzpgdq5w3jhxapqd9h8vmmfvdjs9qyyssqj7lf2w4m587g04n4t0ferdv0vnwftzca0xuc9yxycng78cnhrvmyw2mzaa8t76jskpypqnwqhp9xh0vnwxz90jytd34vrmhcngsnl8qplz7ylk";
console.log("Lightning invoice:", invoice);

Estimate Fees

Get a fee estimate for the Lightning payment to understand costs.

const feeEstimate = await wallet.getLightningSendFeeEstimate({
  encodedInvoice: invoice
});
console.log("Fee estimate:", feeEstimate);

Pay Invoice

Send the Lightning payment with appropriate fee limits.

const payment = await wallet.payLightningInvoice({
  invoice: invoice,
  maxFeeSats: 5, // Maximum fee to pay
  preferSpark: true // Prefer Spark transfers when possible
});
console.log("Payment initiated:", payment);

Monitor Payment

Track the payment status until completion.

const paymentStatus = await wallet.getLightningSendRequest(payment.id);
console.log("Payment status:", paymentStatus.status);

Pay Lightning Invoice

Send Bitcoin from your Spark wallet to any Lightning Network invoice. payLightningInvoice(params) Pays a Lightning invoice using your Spark wallet balance.

const payment = await wallet.payLightningInvoice({
  invoice: "lnbcrt1u1pnm7ammpp4v84f05tl0kzt6g95g056athdpp8f8azvg6d7epz74z562ymer9jqsp5nc50gazvp0e98u42jlu653rw0eutcl067nqq924hf89q4la4kd9sxq9z0rgqnp4qdnmwu8v22cvq9xsv2l05cn9rre7xlcgdtntxawf8m0zxq3qemgzqrzjqtr2vd60g57hu63rdqk87u3clac6jlfhej4kldrrjvfcw3mphcw8sqqqqrj0q7ew45qqqqqqqqqqqqqq9qcqzpgdq5w3jhxapqd9h8vmmfvdjs9qyyssqj7lf2w4m587g04n4t0ferdv0vnwftzca0xuc9yxycng78cnhrvmyw2mzaa8t76jskpypqnwqhp9xh0vnwxz90jytd34vrmhcngsnl8qplz7ylk",
  maxFeeSats: 5,
  preferSpark: true,
  amountSatsToSend: 1000 // Only for zero-amount invoices
});

console.log("Payment Response:", payment);

Show Parameters

string

required

The BOLT11-encoded Lightning invoice to pay

number

required

Maximum fee in satoshis to pay for the invoice

boolean

default:"false"

When true, Spark wallets will initiate a Spark transfer instead of a Lightning transfer if a valid Spark address is found in the invoice

number

Amount in satoshis to send (only used for zero-amount invoices)

Show Returns

LightningSendRequest

required

The Lightning payment request details including ID and status

Get Fee Estimate

Estimate the fees for a Lightning payment before sending. getLightningSendFeeEstimate(params) Gets an estimated fee for sending a Lightning payment.

const feeEstimate = await wallet.getLightningSendFeeEstimate({
  encodedInvoice: "lnbcrt1u1pnm7ammpp4v84f05tl0kzt6g95g056athdpp8f8azvg6d7epz74z562ymer9jqsp5nc50gazvp0e98u42jlu653rw0eutcl067nqq924hf89q4la4kd9sxq9z0rgqnp4qdnmwu8v22cvq9xsv2l05cn9rre7xlcgdtntxawf8m0zxq3qemgzqrzjqtr2vd60g57hu63rdqk87u3clac6jlfhej4kldrrjvfcw3mphcw8sqqqqrj0q7ew45qqqqqqqqqqqqqq9qcqzpgdq5w3jhxapqd9h8vmmfvdjs9qyyssqj7lf2w4m587g04n4t0ferdv0vnwftzca0xuc9yxycng78cnhrvmyw2mzaa8t76jskpypqnwqhp9xh0vnwxz90jytd34vrmhcngsnl8qplz7ylk"
});

console.log("Estimated fee:", feeEstimate);

Show Parameters

string

required

The BOLT11-encoded Lightning invoice

Show Returns

LightningSendFeeEstimate

required

The estimated fee for the Lightning payment

Monitor Payment Status

Track the status of your Lightning payment. getLightningSendRequest(id) Gets a Lightning send request by ID to check payment status.

const paymentStatus = await wallet.getLightningSendRequest(paymentId);
console.log("Payment status:", paymentStatus.status);
console.log("Payment amount:", paymentStatus.amountSats);

// Check if payment is complete
if (paymentStatus.status === "TRANSFER_COMPLETED") {
  console.log("Payment completed successfully!");
}

Show Parameters

string

required

The ID of the Lightning send request

Show Returns

LightningSendRequest

required

The Lightning send request details including status and amount

Zero-Amount Invoices

Spark supports paying zero-amount Lightning invoices, which allow you to specify the amount when making the payment.

Zero-amount invoices are not widely supported across the Lightning Network. Some exchanges, such as Binance, currently do not support them.

Paying Zero-Amount Invoices

When paying a zero-amount invoice, you need to specify the amount using the amountSatsToSend parameter:

// Pay a zero-amount invoice with a specific amount
const payment = await wallet.payLightningInvoice({
  invoice: "lnbc...", // Zero-amount Lightning invoice
  maxFeeSats: 5,
  amountSatsToSend: 1000, // Specify the amount to send (in satoshis)
});

console.log("Zero-amount Payment Response:", payment);

The amountSatsToSend parameter is only used for zero-amount invoices. For regular invoices with a fixed amount, this parameter is ignored.

Spark Transfer Preference

When paying Lightning invoices, you can enable Spark transfer preference to automatically use Spark transfers when possible.

// Pay with Spark preference enabled
const payment = await wallet.payLightningInvoice({
  invoice: "lnbc...", // Lightning invoice (potentially with embedded Spark address)
  maxFeeSats: 5,
  preferSpark: true, // Defaults to false
});

console.log("Payment Response:", payment);

When preferSpark is set to true, Spark wallets will:

Initiate a Spark transfer instead of a Lightning transfer if a valid Spark address is found in the invoice
Fall back to regular Lightning payment if no Spark address is found

Real-time Payment Monitoring

Monitor Lightning payment status by polling.

The transfer:claimed event does not fire for outgoing Lightning payments. Use getLightningSendRequest() to poll payment status.

// For outgoing Lightning payments, poll the status:
const checkPaymentStatus = async (paymentId) => {
  const paymentStatus = await wallet.getLightningSendRequest(paymentId);
  
  switch (paymentStatus.status) {
    case "TRANSFER_COMPLETED":
      console.log("Lightning payment completed!");
      return true;
    case "TRANSFER_FAILED":
      console.log("Lightning payment failed");
      return false;
    default:
      console.log("Lightning payment pending...");
      setTimeout(() => checkPaymentStatus(paymentId), 5000); // Check again in 5 seconds
      return false;
  }
};

// For INCOMING transfers/deposits, use events:
wallet.on("transfer:claimed", (transferId, updatedBalance) => {
  console.log(`Incoming transfer ${transferId} claimed. New balance: ${updatedBalance} sats`);
});

Fee Recommendations

We recommend setting the maximum routing fee to whichever is greater:

5 sats (minimum fee)
17 bps × transaction amount (0.17% of the transaction)

// Calculate recommended fee
const amountSats = 10000; // Your payment amount
const recommendedFee = Math.max(5, Math.ceil(amountSats * 0.0017)); // 17 bps = 0.17%

const payment = await wallet.payLightningInvoice({
  invoice: "lnbc...",
  maxFeeSats: recommendedFee
});

Introduction

Installation

Wallet

Transfers

Deposits

Withdrawals

Fees

Spark Signer Interface

Tools

Withdraw to Lightning

Lightning Withdrawal Flow

Pay Lightning Invoice

Get Fee Estimate

Monitor Payment Status

Zero-Amount Invoices

Paying Zero-Amount Invoices

Spark Transfer Preference

Real-time Payment Monitoring

Fee Recommendations

​Lightning Withdrawal Flow

​Pay Lightning Invoice

​Get Fee Estimate

​Monitor Payment Status

​Zero-Amount Invoices

​Paying Zero-Amount Invoices

​Spark Transfer Preference

​Real-time Payment Monitoring

​Fee Recommendations

Lightning Withdrawal Flow

Pay Lightning Invoice

Get Fee Estimate

Monitor Payment Status

Zero-Amount Invoices

Paying Zero-Amount Invoices

Spark Transfer Preference

Real-time Payment Monitoring

Fee Recommendations