Helius Sender: Ultra-Low Latency Solana Transaction Submission

import { pipe } from "@solana/kit";
import {
  createSolanaRpc,
  createTransactionMessage,
  setTransactionMessageFeePayerSigner,
  setTransactionMessageLifetimeUsingBlockhash,
  appendTransactionMessageInstruction,
  signTransactionMessageWithSigners,
  lamports,
  getBase64EncodedWireTransaction,
  createKeyPairSignerFromBytes,
  address,
} from "@solana/kit";
import { getTransferSolInstruction } from "@solana-program/system";
import {
  getSetComputeUnitLimitInstruction,
  getSetComputeUnitPriceInstruction,
} from "@solana-program/compute-budget";
import bs58 from 'bs58';

const TIP_ACCOUNTS = [
  "4ACfpUFoaSD9bfPdeu6DBt89gB6ENTeHBXCAi87NhDEE",
  "D2L6yPZ2FmmmTKPgzaMKdhu6EWZcTpLy1Vhx8uvZe7NZ",
  "9bnz4RShgq1hAnLnZbP8kbgBg1kEmcJBYQq3gQbmnSta"
  // ... more tip accounts available
];

async function sendWithSender(
  privateKeyB58: string,
  recipientAddress: string
): Promise<string> {
  // Load signer from base58 private key
  const ownerSigner = await createKeyPairSignerFromBytes(bs58.decode(privateKeyB58));

  // Init RPC and fetch blockhash
  const rpc = createSolanaRpc('https://mainnet.helius-rpc.com/?api-key=YOUR_API_KEY');
  const { value: blockhash } = await rpc.getLatestBlockhash().send();

  // Build + sign transaction
  const tx = pipe(
    createTransactionMessage({ version: 0 }),
    (m) => setTransactionMessageFeePayerSigner(ownerSigner, m),
    (m) => setTransactionMessageLifetimeUsingBlockhash(blockhash, m),
    (m) => appendTransactionMessageInstruction(getSetComputeUnitLimitInstruction({ units: 100_000 }), m),
    (m) => appendTransactionMessageInstruction(getSetComputeUnitPriceInstruction({ microLamports: 200_000 }), m),
    (m) =>
      appendTransactionMessageInstruction(
        getTransferSolInstruction({
          source: ownerSigner,
          destination: address(recipientAddress),
          amount: lamports(1_000_000_000n), // 1 SOL
        }),
        m
      ),
    (m) =>
      appendTransactionMessageInstruction(
        getTransferSolInstruction({
          source: ownerSigner,
          destination: address(TIP_ACCOUNTS[Math.floor(Math.random() * TIP_ACCOUNTS.length)]),
          amount: lamports(1_000_000n), // 0.001 SOL
        }),
        m
      )
  );

  const signedTx = await signTransactionMessageWithSigners(tx);
  const base64Tx = getBase64EncodedWireTransaction(signedTx);

  console.log('Sending transaction via Sender endpoint...');

  // Send via Sender
  const res = await fetch("https://sender.helius-rpc.com/fast", {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({
      jsonrpc: "2.0",
      id: Date.now().toString(),
      method: "sendTransaction",
      params: [
        base64Tx,
        { encoding: "base64", skipPreflight: true, maxRetries: 0 },
      ],
    }),
  });

  const { result: sig, error } = await res.json();
  if (error) throw new Error(error.message);

  console.log("Transaction sent: ", sig);
  return sig;
}

// Usage
sendWithSender('YOUR_PRIVATE_KEY', 'RECIPIENT_ADDRESS');