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Overview

Sovran integrates Lightning Network payments through the Cashu protocol’s melt/mint operations. Users can pay Lightning invoices, send to Lightning addresses, and handle LNURL-pay requests.

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Payment String Processing

The useProcessPaymentString hook (hooks/coco/useProcessPaymentString.ts) handles all Lightning payment formats:

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Supported Formats

  1. Lightning invoices (BOLT11)
  2. Lightning addresses (user@domain.com)
  3. LNURL-pay URLs (lnurlp://…)
  4. Ecash tokens (cashuA…)
  5. NUT-18 payment requests (creqA…)
  6. HTTP/HTTPS mint URLs
  7. Nostr pubkeys (npub…)

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Invoice Detection

if (
  (isLightningAddress(lnTrim(scanning.data)) ||
    isLnurlp(lnTrim(scanning.data)) ||
    isLightningInvoice(lnTrim(scanning.data))) &&
  selectedMint
) {
  const trimmedData = lnTrim(scanning.data);
  const amount = getLightningAmount(trimmedData);
  const isInvoice = isLightningInvoice(trimmedData);

  addScan(scanning.data, trimmedData, 'lightning', source);

  if (isInvoice && amount) {
    // Direct navigation to melt quote screen
    router.navigate({
      pathname: '/(send-flow)/meltQuote',
      params: { invoice: trimmedData },
    });
    return { urInProgress: false };
  }

  // Lightning address/LNURL without amount
  router.navigate({
    pathname: '/(send-flow)/currency',
    params: {
      to: 'meltQuote',
      lnUrlOrAddress: trimmedData,
      unit,
    },
  });
}
From hooks/coco/useProcessPaymentString.ts:333-367.

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Lightning Utilities

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Invoice Parsing

The helper/coco/utils.ts module provides Lightning invoice utilities:

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Extract Amount

export function getLightningAmount(invoice: string): number {
  try {
    const decoded = decode(invoice);
    const amount = decoded?.sections?.find((route) => route?.name === 'amount')?.value;
    return amount ? amount / 1000 : 0; // Convert millisats to sats
  } catch {
    return 0;
  }
}

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Extract Timestamp

export function getLightningTimestamp(invoice: string): number {
  try {
    const decoded = decode(invoice);
    const timestamp = decoded?.sections?.find((route) => route?.name === 'timestamp')?.value;
    return timestamp || 0;
  } catch {
    return 0;
  }
}

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Validate Invoice

export const isLightningInvoice = (invoice: string): boolean => {
  try {
    decode(invoice);
    return true;
  } catch {
    return false;
  }
};

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URI Trimming

Normalizes Lightning URIs by removing common prefixes: 
export function lnTrim(str: string) {
  if (!str || !_.isString(str)) {
    return '';
  }
  str = str.trim().toLowerCase();
  const uriPrefixes = [
    'lightning:',
    'lightning=',
    'lightning://',
    'lnurlp://',
    'lnurlp=',
    'lnurlp:',
    'lnurl:',
    'lnurl=',
    'lnurl://',
  ];
  uriPrefixes.forEach((prefix) => {
    if (!str.startsWith(prefix)) {
      return;
    }
    str = str.slice(prefix.length).trim();
  });
  return str.trim();
}
From helper/coco/utils.ts:162-185.

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LNURL Support

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Lightning Address Validation

const LN_ADDRESS_REGEX =
  /^((?:[^<>()[\]\\.,;:\s@"]+(?:\.[^<>()[\]\\.,;:\s@"]+)*)|(?:".+"))@((?:\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(?:(?:[a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;

export const isLightningAddress = (address: string): boolean => {
  if (!address) return false;
  return LN_ADDRESS_REGEX.test(address);
};

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LNURL-Pay URL Validation

const LNURLP_REGEX = /^lnurlp:\/\/([\w-]+\.)+[\w-]+(:\d{1,5})?(\/[\w-./?%&=]*)?$/;

export const isLnurlp = (url: string): boolean => {
  if (!url) return false;
  return LNURLP_REGEX.test(url);
};

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Request Invoice from LNURL

export const requestInvoiceFromLnurl = async (
  lnUrlOrAddress: string,
  amountSats: number
): Promise<string> => {
  const params = await getLnurlPayParams(lnUrlOrAddress);
  if (!params || !params.callback) {
    throw new Error('Invalid LNURL or lightning address');
  }

  const amountMsats = amountSats * 1000;

  if (amountMsats < params.minSendable || amountMsats > params.maxSendable) {
    throw new Error(
      `Amount must be between ${params.minSendable / 1000} and ${params.maxSendable / 1000} sats`
    );
  }

  const response = await fetch(`${params.callback}?amount=${amountMsats}`);
  const data = await response.json();

  if (!data.pr) {
    throw new Error('No invoice returned from LNURL endpoint');
  }

  return data.pr;
};
From helper/coco/utils.ts:284-309.

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Melt Operations

The useMeltWithHistory hook manages Lightning payment execution: 
import type { MeltQuoteBolt11Response } from '@cashu/cashu-ts';
import type { MeltHistoryEntry } from 'coco-cashu-core';
import { useManager } from 'coco-cashu-react';

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Melt Flow

  1. Prepare melt quote - Get quote from mint for invoice amount + fees
  2. Execute melt - Burn ecash tokens and pay Lightning invoice
  3. Track history - Record melt operation in transaction history
  4. Handle errors - Rollback on failure, preserve tokens
From hooks/coco/useMeltWithHistory.ts:1-12.

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Payment Flows

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Direct Invoice Payment

When scanning an invoice with an amount:

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Lightning Address Payment

When sending to a Lightning address:

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NFC Lightning Detection

NFC payments can detect Lightning invoices and redirect to the appropriate flow: 
// From helper/nfc/payment.ts:198-212
const trimmedForLightning = lnTrim(paymentRequest);
if (isLightningInvoice(trimmedForLightning)) {
  log('Lightning invoice detected via NFC');
  const lnAmount = getLightningAmount(trimmedForLightning);
  if (onLightningInvoice) {
    await releaseNfc();
    onLightningInvoice(trimmedForLightning, lnAmount);
    return { paymentRequest, mintUrl: '', amount: lnAmount };
  }
  throw new NfcError(
    'Lightning invoice detected. Please use the Lightning payment flow.',
    'LIGHTNING_INVOICE_DETECTED'
  );
}

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Lightning Operations Hook

The useLightningOperations hook provides high-level Lightning operations: 
import { useManager } from 'coco-cashu-react';

export function useLightningOperations() {
  const manager = useManager();
  
  // Provides:
  // - createMeltQuote(mintUrl, invoice)
  // - executeMelt(quoteId)
  // - checkMeltStatus(quoteId)
  // - cancelMelt(quoteId)
}
From hooks/coco/useLightningOperations.ts:3.

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Scan History Integration

All Lightning scans are tracked: 
addScan(scanning.data, trimmedData, 'lightning', source);
Scan sources include:
  • qr - QR code scanner
  • paste - Clipboard paste
  • deeplink - App deep link
  • nfc - NFC tap payment

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Key Features

BOLT11 Support

Full support for Lightning invoices with amount extraction and validation

LNURL Integration

Native LNURL-pay and Lightning address support without external libraries

Automatic Routing

Smart routing based on invoice amount and mint availability

NFC Detection

Automatic detection and handling of Lightning invoices via NFC

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