Sender chỉ dùng SWQOS: Gửi với độ trễ thấp và chi phí tối ưu

import { 
  Connection, 
  TransactionMessage,
  VersionedTransaction,
  SystemProgram, 
  PublicKey,
  Keypair,
  LAMPORTS_PER_SOL,
  ComputeBudgetProgram
} from '@solana/web3.js';
import bs58 from 'bs58';

const PRIV_B58 = 'Your Private Key';
const RECIPIENT = 'Recipient Address';
const HELIUS_API_KEY = 'Your API Key';
const TIP_ACCOUNTS = [
  "4ACfpUFoaSD9bfPdeu6DBt89gB6ENTeHBXCAi87NhDEE",
  "D2L6yPZ2FmmmTKPgzaMKdhu6EWZcTpLy1Vhx8uvZe7NZ",
  "9bnz4RShgq1hAnLnZbP8kbgBg1kEmcJBYQq3gQbmnSta",
  "5VY91ws6B2hMmBFRsXkoAAdsPHBJwRfBht4DXox3xkwn",
  "2nyhqdwKcJZR2vcqCyrYsaPVdAnFoJjiksCXJ7hfEYgD",
  "2q5pghRs6arqVjRvT5gfgWfWcHWmw1ZuCzphgd5KfWGJ",
  "wyvPkWjVZz1M8fHQnMMCDTQDbkManefNNhweYk5WkcF",
  "3KCKozbAaF75qEU33jtzozcJ29yJuaLJTy2jFdzUY8bT",
  "4vieeGHPYPG2MmyPRcYjdiDmmhN3ww7hsFNap8pVN3Ey",
  "4TQLFNWK8AovT1gFvda5jfw2oJeRMKEmw7aH6MGBJ3or"
];

async function sendSwqosOnly(
  keypair: Keypair,
  recipientAddress: string
): Promise<string> {
  const connection = new Connection(
    `https://mainnet.helius-rpc.com/?api-key=${HELIUS_API_KEY}`
  );

  const { value: { blockhash } } = await connection.getLatestBlockhashAndContext('confirmed');

  // Build transaction: priority fee + recipient transfer + minimum SWQOS-only tip
  const transaction = new VersionedTransaction(
    new TransactionMessage({
      instructions: [
        ComputeBudgetProgram.setComputeUnitLimit({ units: 100_000 }),
        ComputeBudgetProgram.setComputeUnitPrice({ microLamports: 200_000 }),
        SystemProgram.transfer({
          fromPubkey: keypair.publicKey,
          toPubkey: new PublicKey(recipientAddress),
          lamports: 0.001 * LAMPORTS_PER_SOL,
        }),
        SystemProgram.transfer({
          fromPubkey: keypair.publicKey,
          toPubkey: new PublicKey(TIP_ACCOUNTS[Math.floor(Math.random() * TIP_ACCOUNTS.length)]),
          lamports: 0.000005 * LAMPORTS_PER_SOL, // SWQOS-only minimum tip
        })
      ],
      payerKey: keypair.publicKey,
      recentBlockhash: blockhash,
    }).compileToV0Message()
  );

  transaction.sign([keypair]);

  // Note the ?swqos_only=true query parameter
  const SENDER_ENDPOINT = 'https://sender.helius-rpc.com/fast?swqos_only=true';
  // Backend: use the regional HTTP endpoint closest to your servers
  // const SENDER_ENDPOINT = 'http://slc-sender.helius-rpc.com/fast?swqos_only=true';

  const response = await fetch(SENDER_ENDPOINT, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({
      jsonrpc: '2.0',
      id: Date.now().toString(),
      method: 'sendTransaction',
      params: [
        Buffer.from(transaction.serialize()).toString('base64'),
        {
          encoding: 'base64',
          skipPreflight: true, // Optional: skip for lower latency
          maxRetries: 0
        }
      ]
    })
  });

  const json = await response.json();
  if (json.error) {
    throw new Error(json.error.message);
  }

  console.log('Transaction sent:', json.result);
  return json.result;
}

// Usage
sendSwqosOnly(Keypair.fromSecretKey(bs58.decode(PRIV_B58)), RECIPIENT);