Solana: MEV protection with Jito

import {
  createSolanaRpc,
  address,
  lamports,
  pipe,
  createKeyPairSignerFromBytes,
  getBase58Encoder,
  createTransactionMessage,
  setTransactionMessageFeePayerSigner,
  setTransactionMessageLifetimeUsingBlockhash,
  appendTransactionMessageInstructions,
  signTransactionMessageWithSigners,
  getBase64EncodedWireTransaction,
  AccountRole,
} from "@solana/kit";
import { getTransferSolInstruction } from "@solana-program/system";
import "dotenv/config";

// Use your Chainstack endpoint for reads
const rpc = createSolanaRpc(process.env.SOLANA_RPC!);
// @solana/kit decodes base58, so no separate bs58 package is needed
const payer = await createKeyPairSignerFromBytes(
  getBase58Encoder().encode(process.env.PRIVATE_KEY!)
);

// Jito block engine for sends
const JITO_ENDPOINT =
  "https://mainnet.block-engine.jito.wtf/api/v1/transactions";

// Any valid pubkey starting with "jitodontfront". Does not need to exist on-chain.
const DONT_FRONT = address("jitodontfront111111111111111111111111111111");

// Jito tip accounts — pick one at random to reduce contention
const TIP_ACCOUNTS = [
  "96gYZGLnJYVFmbjzopPSU6QiEV5fGqZNyN9nmNhvrZU5",
  "HFqU5x63VTqvQss8hp11i4wVV8bD44PvwucfZ2bU7gRe",
  "Cw8CFyM9FkoMi7K7Crf6HNQqf4uEMzpKw6QNghXLvLkY",
  "ADaUMid9yfUytqMBgopwjb2DTLSokTSzL1zt6iGPaS49",
  "DfXygSm4jCyNCybVYYK6DwvWqjKee8pbDmJGcLWNDXjh",
  "ADuUkR4vqLUMWXxW9gh6D6L8pMSawimctcNZ5pGwDcEt",
  "DttWaMuVvTiduZRnguLF7jNxTgiMBZ1hyAumKUiL2KRL",
  "3AVi9Tg9Uo68tJfuvoKvqKNWKkC5wPdSSdeBnizKZ6jT",
];

// Append the dontfront marker as a read-only account to any instruction
function addDontFront(instruction) {
  return {
    ...instruction,
    accounts: [
      ...(instruction.accounts ?? []),
      { address: DONT_FRONT, role: AccountRole.READONLY },
    ],
  };
}

function randomTipAccount() {
  return address(TIP_ACCOUNTS[Math.floor(Math.random() * TIP_ACCOUNTS.length)]);
}

async function sendWithMEVProtection() {
  const { value: latestBlockhash } = await rpc.getLatestBlockhash().send();

  // Your actual instruction — add dontfront to it
  const transferIx = addDontFront(
    getTransferSolInstruction({
      source: payer,
      destination: payer.address,
      amount: lamports(1_000_000n), // 0.001 SOL
    })
  );

  // Jito tip — minimum 1000 lamports
  const tipIx = getTransferSolInstruction({
    source: payer,
    destination: randomTipAccount(),
    amount: lamports(1000n),
  });

  const message = pipe(
    createTransactionMessage({ version: 0 }),
    (m) => setTransactionMessageFeePayerSigner(payer, m),
    (m) => setTransactionMessageLifetimeUsingBlockhash(latestBlockhash, m),
    (m) => appendTransactionMessageInstructions([transferIx, tipIx], m)
  );

  const signedTransaction = await signTransactionMessageWithSigners(message);

  // Send through Jito block engine, NOT standard RPC
  const serialized = getBase64EncodedWireTransaction(signedTransaction);
  const response = await fetch(JITO_ENDPOINT, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({
      jsonrpc: "2.0",
      id: 1,
      method: "sendTransaction",
      params: [serialized, { encoding: "base64" }],
    }),
  });

  const result = await response.json();
  console.log("Sent with dontfront protection:", result.result);
}

sendWithMEVProtection();