Web integration · Stellar / USDC

async function createMoneyGramSession(req, res) {  const secretKey = process.env.MONEYGRAM_SK // ramps_sk_sbox_...  if (!secretKey) return res.status(500).json({ error: 'Secret key not configured' })   const { walletAddress } = req.body ?? {}   const mgiRes = await fetch('https://playground.xramps.moneygram.com/api/v1/sessions', {    method: 'POST',    headers: {      'Content-Type': 'application/json',      'x-api-key': secretKey,    },    body: JSON.stringify({      walletAddress, // G... address of the end user      chain: 'stellar',    }),  })   const data = await mgiRes.json()  if (!mgiRes.ok) return res.status(mgiRes.status).json(data)   return res.status(200).json({    sessionToken: data.sessionToken,    sessionId: data.sessionId,    widgetUrl: data.widgetUrl,  })}

<script src="https://playground.xramps.moneygram.com/sdk/index.global.js"></script>

const { createRamps } = window.RampsSDK const session = await fetch('/api/moneygram-session', {  method: 'POST',  headers: { 'Content-Type': 'application/json' },  body: JSON.stringify({ walletAddress: userGAddress }),}).then((r) => r.json()) const ramps = createRamps({  container: document.getElementById('ramps-widget-container'),  sessionToken: session.sessionToken,  widgetUrl: session.widgetUrl,   wallet: {    address: userGAddress,    chain: 'stellar',    asset: 'USDC',    walletType: 'non-custodial',  },   onSignTransaction: async (tx) => {    // Step 3: sign Stellar USDC transfer    return await signStellarUsdcTransfer(tx)  },   onComplete: (transaction) => {    console.log('Done:', transaction.referenceNumber, transaction.type)  },   onError: (err) => console.error(err),}) ramps.open()

const widgetUrl = new URL(session.widgetUrl)widgetUrl.searchParams.set('mode', 'on-ramp') const ramps = createRamps({  // ...sessionToken, wallet, transaction: { type: 'on-ramp' }  widgetUrl: widgetUrl.toString(),  mode: 'on-ramp',})

import {  Asset,  BASE_FEE,  Horizon,  Keypair,  Memo,  Networks,  Operation,  TransactionBuilder,} from '@stellar/stellar-sdk' const TESTNET_USDC_ISSUER = 'GBBD47IF6LWK7P7MDEVSCWR7DPUWV3NY3DTQEVFL4NAT4AQH3ZLLFLA5'const MAINNET_USDC_ISSUER = 'GA5ZSEJYB37JRC5AVCIA5MOP4RHTM335X2KGX3IHOJAPP5RE34K4KZVN' function usdcIssuer(requiredNetwork: 'mainnet' | 'testnet'): string {  if (requiredNetwork === 'mainnet') return MAINNET_USDC_ISSUER  return TESTNET_USDC_ISSUER} /** Settlement memos are Stellar ID memos (unsigned 64-bit), not text memos. */function settlementMemo(memo: string) {  if (!/^[0-9]+$/.test(memo)) {    throw new Error('Settlement memo must be a numeric Stellar ID memo')  }  return Memo.id(memo)} async function signStellarUsdcTransfer(tx: {  to: string  amount: string  memo?: string  tokenAddress?: string  issuer?: string  requiredNetwork?: string}): Promise<string> {  if (tx.requiredNetwork !== 'mainnet' && tx.requiredNetwork !== 'testnet') {    throw new Error('Sign payload is missing requiredNetwork')  }  const requiredNetwork = tx.requiredNetwork  const networkPassphrase =    requiredNetwork === 'mainnet' ? Networks.PUBLIC : Networks.TESTNET  const horizon =    requiredNetwork === 'mainnet'      ? new Horizon.Server('https://horizon.stellar.org')      : new Horizon.Server('https://horizon-testnet.stellar.org')   const sourceKeypair = Keypair.fromSecret(process.env.USER_SECRET!) // your wallet signing  // tokenAddress is the asset code (USDC). Prefer issuer on the payload.  const usdc = new Asset(    tx.tokenAddress ?? 'USDC',    tx.issuer ?? usdcIssuer(requiredNetwork),  )   const account = await horizon.loadAccount(sourceKeypair.publicKey())   let builder = new TransactionBuilder(account, {    fee: BASE_FEE,    networkPassphrase,  }).addOperation(    Operation.payment({      destination: tx.to,      asset: usdc,      amount: tx.amount,    })  )   if (tx.memo?.trim()) {    builder = builder.addMemo(settlementMemo(tx.memo.trim()))  }   const transaction = builder.setTimeout(180).build()  transaction.sign(sourceKeypair)   const result = await horizon.submitTransaction(transaction)  return result.hash}