How to Submit Transactions to Public Mempool

Learn how to submit transactions to the BNB Chain public mempool through GetBlock's BDN fast path.

This process involves submitting transactions to the BNB Chain public mempool via GetBlock's BDN fast path. Your transaction propagates to validators significantly faster than through standard P2P gossip, increasing the probability of earlier block inclusion.

When to Use Public Mempool

Use public mempool submission when:

• You want faster propagation without hiding your transaction

• MEV exposure is acceptable for your use case

• You're competing on speed rather than privacy

• You need broad validator visibility quickly

For MEV-sensitive transactions, see Private Transactions instead.

Sample Request

Endpoint

wss://shared.eu-central-1.getblock.io/<ACCESS_TOKEN>

Method

blxr_tx

Transaction Parameters

Parameter	Type	Required	Description
nonce	int	Yes	Transaction count for your address
to	string	Yes	Recipient address
value	BigInt	Yes	Amount in wei
gasPrice	BigInt	Yes	Gas price (minimum 3 gwei)
gasLimit	int	Yes	Gas limit for execution
data	string	No	Calldata for contract calls
chainId	int	Yes	56 for BSC Mainnet

Request Format

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "blxr_tx",
  "params": ["0x<signed_transaction_hex>"]
}

Response Format

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x<transaction_hash>"
}

How to Submit a Transaction to Public Mempool

1

Set up the project

npm

mkdir transaction-public-mempool
cd transaction-public-mempool
npm init -y
npm install ws ethers dotenv

yarn

mkdir transaction-public-mempool
cd transaction-public-mempool
yarn init -y
yarn ws ethers dotenv

2

Create a new file named index.js. This is where you will make your first call.

3

Set the ES module "type": "module" in your package.json.

4

Create .env file and add the following:

ACCESS_TOKEN=your-accelerated-node-endpoint
RPC_URL=your-normal-bsc-node-endppoint //e.g https
PRIVATE_KEY=your-wallet-private-key
TO_ADDRESS=the-receiver-address

5

Add the following code to index.js:

6

import WebSocket from "ws";
import { ethers } from "ethers";
import "dotenv/config";

7

Create and Sign Your Transaction

const PRIVATE_KEY = process.env.PRIVATE_KEY;
const RPC_URL = process.env.RPC_URL;
const provider = new ethers.JsonRpcProvider(RPC_URL);
const wallet = new ethers.Wallet(PRIVATE_KEY, provider);

// Get current nonce
const nonce = await provider.getTransactionCount(wallet.address);
// Build transaction
const tx = {
  nonce: nonce,
  to: process.env.TO_ADDRESS,
  value: ethers.parseEther("0.001"),
  gasPrice: ethers.parseUnits("3", "gwei"), // Minimum 3 gwei for BSC
  gasLimit: 21000,
  chainId: 56, // BSC Mainnet
};
// Sign transaction
const signedTx = await wallet.signTransaction(tx); 
const signedTxNoPrefix = signedTx.startsWith("0x")
  ? signedTx.slice(2)
  : signedTx;

8

Submit via WebSocket

const ws = new WebSocket(process.env.ACCESS_TOKEN);
ws.on("open", () => {
  ws.send(
    JSON.stringify({
      jsonrpc: "2.0",
      id: 1,
      method: "blxr_tx",
      params: {"transaction": signedTxNoPrefix},
    }),
  );
});
ws.on("message", (data) => {
  const response = JSON.parse(data);
  if (response.result?.txHash) {
  const hash = response.result.txHash;
  console.log("TX Hash:", hash);
  console.log(`https://bscscan.com/tx/${hash}`);
} else if (response.error) {
    console.error("❌ Error:", response.error.message);
  }
  ws.close();
});

9

Response

01f86c380384b2d05e0082520894d26ea0f03100358b2ebd4c9638f042aada9a1bcf87038d7ea4c6800080c001a04647f98754480337ae409bcc225f2d62b706b47f31385221421cea20e41080b0a03ae32f07bb7110c4153c2ab121c152db7d3030d54cc0c5341f0b75b20e3d439d
TX Hash: 00d4fe2db5c667ce549318cf621913af1bcb130022ec51020cbb6cae2b7eedce
https://bscscan.com/tx/00d4fe2db5c667ce549318cf621913af1bcb130022ec51020cbb6cae2b7eedce

Complete Example: BNB Transfer

import WebSocket from "ws";
import { ethers } from "ethers";
import "dotenv/config";

const PRIVATE_KEY = process.env.PRIVATE_KEY;
const RPC_URL = process.env.RPC_URL;
const provider = new ethers.JsonRpcProvider(RPC_URL);
const wallet = new ethers.Wallet(PRIVATE_KEY, provider);


// Get current nonce
const nonce = await provider.getTransactionCount(wallet.address);

// Build transaction
const tx = {
  nonce: nonce,
  to: "0xd26ea0f03100358b2Ebd4c9638f042aAda9a1BcF",
  value: ethers.parseEther("0.001"),
  gasPrice: ethers.parseUnits("3", "gwei"), // Minimum 3 gwei for BSC
  gasLimit: 21000,
  chainId: 56, // BSC Mainnet
};

// Sign transaction
const signedTx = await wallet.signTransaction(tx); // e.g. "0xabcdef..."
const signedTxNoPrefix = signedTx.startsWith("0x")
  ? signedTx.slice(2)
  : signedTx;

console.log(signedTxNoPrefix);

const ws = new WebSocket(process.env.ACCESS_TOKEN);
ws.on("open", () => {
  ws.send(
    JSON.stringify({
      jsonrpc: "2.0",
      id: 1,
      method: "blxr_tx",
      params: {"transaction": signedTxNoPrefix},
    }),
  );
});

ws.on("message", (data) => {
  const response = JSON.parse(data);
  if (response.result?.txHash) {
  const hash = response.result.txHash;
  console.log("TX Hash:", hash);
  console.log(`https://bscscan.com/tx/${hash}`);
} else if (response.error) {
    console.error("❌ Error:", response.error.message);
  }

  ws.close();
});

Complete Example: Token Swap on PancakeSwap

import WebSocket from 'ws';
import { ethers } from 'ethers';
import 'dotenv/config';

const PRIVATE_KEY = process.env.PRIVATE_KEY;
const RPC_URL = process.env.RPC_URL;

const PANCAKE_ROUTER = '0x10ED43C718714eb63d5aA57B78B54704E256024E';
const WBNB = '0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c';

async function swapBNBForToken(tokenAddress, amountBNB, minAmountOut) {
  const provider = new ethers.JsonRpcProvider(RPC_URL);
  const wallet = new ethers.Wallet(PRIVATE_KEY, provider);
  
  // Router ABI
  const routerABI = [
    'function swapExactETHForTokens(uint256 amountOutMin, address[] path, address to, uint256 deadline) payable'
  ];
  const router = new ethers.Contract(PANCAKE_ROUTER, routerABI, wallet);
  
  // Build swap calldata
  const deadline = Math.floor(Date.now() / 1000) + 300;  // 5 minutes
  const swapData = router.interface.encodeFunctionData('swapExactETHForTokens', [
    minAmountOut,
    [WBNB, tokenAddress],
    wallet.address,
    deadline
  ]);
  
  // Get nonce
  const nonce = await provider.getTransactionCount(wallet.address);
  
  // Build transaction
  const tx = {
    nonce: nonce,
    to: PANCAKE_ROUTER,
    value: ethers.parseEther(amountBNB),
    data: swapData,
    gasPrice: ethers.parseUnits('3', 'gwei'),
    gasLimit: 300000,  // Higher gas limit for swaps
    chainId: 56
  };
  
  // Sign transaction
  const signedTx = await wallet.signTransaction(tx);
  const signedTxNoPrefix = signedTx.startsWith("0x")
 ? signedTx.slice(2)
 : signedTx;
  
  console.log('Swap details:');
  console.log('  Amount:', amountBNB, 'BNB');
  console.log('  Token:', tokenAddress);
  console.log('  Min out:', ethers.formatEther(minAmountOut));
  
  // Submit via BDN
 const ws = new WebSocket(`wss://shared.eu-central-1.getblock.io/${process.env.ACCESS_TOKEN}`);
  
  return new Promise((resolve, reject) => {
    ws.on('open', () => {
      ws.send(JSON.stringify({
        jsonrpc: '2.0',
        id: 1,
        method: "blxr_tx",
        params: {"transaction": signedTxNoPrefix},
      }));
    });
    
    ws.on('message', (data) => {
      const response = JSON.parse(data);
      ws.close();
      
      if (response.result) {
        console.log('\n✅ Swap submitted!');
        console.log('TX Hash:', response.result);
        resolve(response.result);
      } else {
        console.error('\n❌ Error:', response.error);
        reject(response.error);
      }
    });
  });
}

// Usage: Swap 0.001 BNB for BUSD
swapBNBForToken(
  '0xe9e7CEA3DedcA5984780Bafc599bD69ADd087D56',  // BUSD
  '0.001',                                          // 0.001 BNB
  ethers.parseEther('50')                         // Min 50 BUSD
).catch(console.error);

Gas Price Recommendations

Priority	Gas Price	Use Case
Standard	3 gwei	Regular transfers
Fast	5 gwei	Time-sensitive trades
Urgent	10+ gwei	Competitive scenarios

Note: Higher gas prices increase inclusion priority but also increase transaction cost.

Troubleshooting

1. "nonce too low"

Your nonce is behind the network state. Fetch the latest:

const nonce = await provider.getTransactionCount(wallet.address, 'pending');

1. "insufficient funds"

Ensure you have enough BNB for both the transaction value and gas:

Required = value + (gasPrice × gasLimit)

1. "replacement transaction underpriced"

If replacing a pending transaction, increase the gas price by at least 10%:

const newGasPrice = existingGasPrice * 110n / 100n;

1. Transaction not included

• Increase gas price for higher priority

• Check that the transaction is valid

• Verify sufficient balance

Next Steps

For transactions that need MEV protection, see:

• Private Transactions — Hidden from public mempool

• Private Transactions with Tips — Prioritized private submission