I'm trying to execute swap on Pancakeswap with web3.js but I get error

I am new at ethereum development and I am working on a simple script to execute swaps using Pancakeswap.
The code:

const ethers = require('ethers');

const {ChainId, Token, TokenAmount, Fetcher, Pair, Route, Trade, TradeType, Percent} = 

require('@pancakeswap-libs/sdk');

const Web3 = require('web3');

const {JsonRpcProvider} = require("@ethersproject/providers");

require("dotenv").config();

const provider = new JsonRpcProvider('https://bsc-dataseed1.binance.org/');

const web3 = new Web3('wss://apis.ankr.com/wss/c40792ffe3514537be9fb4109b32d257/946dd909d324e5a6caa2b72ba75c5799/binance/full/main');

const { address: admin } = web3.eth.accounts.wallet.add(process.env.PRIVATE_KEY);

console.log(`Modulos cargados`);

// Command Line Input

const InputTokenAddr = web3.utils.toChecksumAddress(process.argv[2]);

// var BUSD = '0xe9e7CEA3DedcA5984780Bafc599bD69ADd087D56';

const OutputTokenAddr = web3.utils.toChecksumAddress(process.argv[3]);

// var WBNB = '0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c';

const InputTokenAmount = process.argv[4]

const Slipage = process.argv[5];

const PANCAKE_ROUTER = process.argv[6];

// const PANCAKE_ROUTER_V2 = '0x10ed43c718714eb63d5aa57b78b54704e256024e';

// const PANCAKE_ROUTER_V1 = '0x05fF2B0DB69458A0750badebc4f9e13aDd608C7F';

// 1/1000 = 0.001

const ONE_ETH_IN_WEI = web3.utils.toBN(web3.utils.toWei('1'));//BN->(BIG NUMBER) || toWei -> Converts any ether value value into wei.

const tradeAmount = ONE_ETH_IN_WEI.div(web3.utils.toBN('1000'));//tradeAmount = ONE_ETH_IN_WEI/1000

console.log(`tradeAmount ` + tradeAmount );

const init = async () => {

    const [INPUT_TOKEN, OUTPUT_TOKEN] = await Promise.all(

        [InputTokenAddr, OutputTokenAddr].map(tokenAddress => (

            new Token(

                ChainId.MAINNET,

                tokenAddress,

                18

            )

        )));

    console.log(` <<<<<------- pair-------->>>>>`);

    const pair = await Fetcher.fetchPairData(INPUT_TOKEN, OUTPUT_TOKEN, provider);

    //console.log(JSON.stringify(pair));

    console.log(` <<<<<------- route-------->>>>>`);

    const route = await new Route([pair], INPUT_TOKEN);

    //console.log(JSON.stringify(route));

    console.log(` <<<<<------- Trade-------->>>>>`);

    const trade = await new Trade(route, new TokenAmount(INPUT_TOKEN, tradeAmount), TradeType.EXACT_INPUT);

    //console.log(JSON.stringify(trade));

    //https://uniswap.org/docs/v2/javascript-SDK/trading/

    const slippageTolerance = new Percent(Slipage, '100'); // 

    console.log("slippageTolerance: " + JSON.stringify(slippageTolerance));

    // create transaction parameters

    const amountOutMin = trade.minimumAmountOut(slippageTolerance).raw;

    const path = [INPUT_TOKEN.address, OUTPUT_TOKEN.address];

    const to = admin;

    const deadline = Math.floor(Date.now() / 1000) + 60 * 20;

    // Create signer

    const wallet = new ethers.Wallet(

        Buffer.from(

        process.env.PRIVATE_KEY, 

        "hex"

        )

    );

    const signer = wallet.connect(provider);

    // Create Pancakeswap ethers Contract

    const pancakeswap = new ethers.Contract(

        PANCAKE_ROUTER,

        ['function swapExactTokensForTokens(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline) external returns (uint[] memory amounts)'],

        signer

    );

    //Allow input token

    if(true)

    {

        console.log(`Allow Pancakeswap <<<<<------- START-------->>>>>`);

        let abi = ["function approve(address _spender, uint256 _value) public returns (bool success)"];

        let contract = new ethers.Contract(INPUT_TOKEN.address, abi, signer);

        let aproveResponse = await contract.approve(PANCAKE_ROUTER, ethers.utils.parseUnits('1000.0', 18), {gasLimit: 100000, gasPrice: 5e9});

        console.log(JSON.stringify(aproveResponse));

        console.log(`Allow Pancakeswap <<<<<------- END-------->>>>>`);

        

    }

    

    if(true)

    {   

        console.log(`Ejecutando transaccion`);      

        var amountInParam = ethers.utils.parseUnits(InputTokenAmount, 18);

        var amountOutMinParam = ethers.utils.parseUnits(web3.utils.fromWei(amountOutMin.toString()), 18);

        

        console.log("amountInParam: " + amountInParam);

        console.log("amountOutMinParam: " + amountOutMinParam);

        console.log("amountOutMin: " + amountOutMin);

                        

        const tx = await pancakeswap.swapExactTokensForTokens(

            amountInParam,

            amountOutMinParam,

            path,

            to,

            deadline,

            { gasLimit: ethers.utils.hexlify(300000), gasPrice: ethers.utils.parseUnits("9", "gwei") }

        );

        console.log(`Tx-hash: ${tx.hash}`)

            const receipt = await tx.wait();

            console.log(`Tx was mined in block: ${receipt.blockNumber}`);

    }

        

}

init();

Normally I set BUSD as input token
And I use pancakeswap v1 or v2 router as router.
When output token is WBNB or BCH, it seems working well on both v1 and v2 router.
But when I set other token as an output token, I get error.
Plz help me.

Dexes such as PancakeSwap and Uniswap operate on pairs in their liquidity pool.

For example BNB/CAKE. When doing a swap with these tokens, you can swap between any token to any token and the router should do it automatically.

Are you sure that you are using the BUSD address correctly?

Are you sure that you are sending in the correct parameters for the Path? You will need to swap to multiple addresses if you plan to do that.

For example BUSD → BNB → CAKE.

Before writing code, you should test to see if your function works on the Test Net.

Can you show me transactions that verify what you are doing makes sense?

This is Pancake Swap’s testnet router.

Thanks for your response.
Of course, BUSD address is correct.
this:
0xe9e7CEA3DedcA5984780Bafc599bD69ADd087D56
I use follow command and parameters are correct.

npm run start 0xe9e7CEA3DedcA5984780Bafc599bD69ADd087D56 0x1af3f329e8be154074d8769d1ffa4ee058b1dbc3 0.001 16 0x10ed43c718714eb63d5aa57b78b54704e256024e

I didnt test on testnet. Can we test on testnet?
I tried to test on testnet but I got error so I gave up.
Could you tell me the way to test code above on testnet?

You can do it on a testnet to make sure the contract function works the way you think it does before doing it with Web3.js

I think you understand the basics of Web3 and have gotten some functions to work, so it’s probably a specific contract function. If you can make a contract function work on chain (on the test net) then you can make it work with web3.js

of course, it works on testnet
But on mainnet in case of some tokens, it doesnt works well

dude i use your code … but this line seems not working on my side

  const wallet = new ethers.Wallet(

    Buffer.from(

    process.env.PRIVATE_KEY, 

    "hex"

    )

);

So I remove the hex and buffer, after i receive I keep receiving Error: transaction failed (transactionHash=“0xe3440188b2dc3dd9bb311d765df67da05631f4d24c6d9bd244bca16bb48305e1”,
do you have any ideas ==

can you show me your error?

Hi Stepan,
You can check this working example that swaps with pancakeswap.finance:

// Helper script that buys ONLYONE token from a specified address specified on text file SPECIFY_ACCOUNTS_YOU_WANT_TO_BUY_FOR_HERE.json
// The amount is specified with 'originalAmountToBuyWith' variable in the source
// The JSON file should have an array with objects with 'address' field and 'privateKey' field.
// Buys ONLYONE for ${bnbAmount} BNB from pancakeswap for address ${targetAccounts[targetIndex].address}
// targetIndex is passed as an argument: process.argv.splice(2)[0]

var fs = require('fs')
var Tx = require('ethereumjs-tx').Transaction;
var Web3 = require('web3')
var Common = require('ethereumjs-common').default;

var web3 = new Web3(new Web3.providers.HttpProvider('https://bsc-dataseed.binance.org/'))
var BSC_FORK = Common.forCustomChain(
    'mainnet',
    {
        name: 'Binance Smart Chain Mainnet',
        networkId: 56,
        chainId: 56,
        url: 'https://bsc-dataseed.binance.org/'
    },
    'istanbul',
);

// SPECIFY_THE_AMOUNT_OF_BNB_YOU_WANT_TO_BUY_FOR_HERE
var originalAmountToBuyWith = '0.007' + Math.random().toString().slice(2,7);
var bnbAmount = web3.utils.toWei(originalAmountToBuyWith, 'ether');

var targetAccounts = JSON.parse(fs.readFileSync('SPECIFY_ACCOUNTS_YOU_WANT_TO_BUY_FOR_HERE.json', 'utf-8'));

var targetIndex = Number(process.argv.splice(2)[0]);
var targetAccount = targetAccounts[targetIndex];

console.log(`Buying ONLYONE for ${originalAmountToBuyWith} BNB from pancakeswap for address ${targetAccount.address}`);

var res = buyOnlyone(targetAccounts[targetIndex], bnbAmount);
console.log(res);

async function buyOnlyone(targetAccount, amount) {

    var amountToBuyWith = web3.utils.toHex(amount);
    var privateKey = Buffer.from(targetAccount.privateKey.slice(2), 'hex')  ;
    var abiArray = JSON.parse(JSON.parse(fs.readFileSync('onlyone-abi.json','utf-8')));
    var tokenAddress = '0xb899db682e6d6164d885ff67c1e676141deaaa40'; // ONLYONE contract address
    var WBNBAddress = '0xbb4cdb9cbd36b01bd1cbaebf2de08d9173bc095c'; // WBNB token address

    // var onlyOneWbnbCakePairAddress = '0xd22fa770dad9520924217b51bf7433c4a26067c2';
    // var pairAbi = JSON.parse(fs.readFileSync('cake-pair-onlyone-bnb-abi.json', 'utf-8'));
    // var pairContract = new web3.eth.Contract(pairAbi, onlyOneWbnbCakePairAddress/*, {from: targetAccount.address}*/);
    var amountOutMin = '100' + Math.random().toString().slice(2,6);
    var pancakeSwapRouterAddress = '0x10ed43c718714eb63d5aa57b78b54704e256024e';

    var routerAbi = JSON.parse(fs.readFileSync('pancake-router-abi.json', 'utf-8'));
    var contract = new web3.eth.Contract(routerAbi, pancakeSwapRouterAddress, {from: targetAccount.address});
    var data = contract.methods.swapExactETHForTokens(
        web3.utils.toHex(amountOutMin),
        [WBNBAddress,
         tokenAddress],
        targetAccount.address,
        web3.utils.toHex(Math.round(Date.now()/1000)+60*20),
    );

    var count = await web3.eth.getTransactionCount(targetAccount.address);
    var rawTransaction = {
        "from":targetAccount.address,
        "gasPrice":web3.utils.toHex(5000000000),
        "gasLimit":web3.utils.toHex(290000),
        "to":pancakeSwapRouterAddress,
        "value":web3.utils.toHex(amountToBuyWith),
        "data":data.encodeABI(),
        "nonce":web3.utils.toHex(count)
    };

    var transaction = new Tx(rawTransaction, { 'common': BSC_FORK });
    transaction.sign(privateKey);

    var result = await web3.eth.sendSignedTransaction('0x' + transaction.serialize().toString('hex'));
    console.log(result)
    return result;
}

Anyone can also contribute to the repository.

1 Like

thanks

I’m trying to call function of my own contract in uniswap.
For example, I want to call my own function of my contract instead of swapETHForExactTokens of UniswapV2Router02 contract.

Thanks for this awesome code. It works perfectly! I’ve also been trying to do the opposite trade with swapExactTokensForETH ( sell tokens buy BNB ) but I keep getting the same message ‘Error: Transaction has been reverted by the EVM:’ and no more details. For instance, here is my TX https://bscscan.com/tx/0xc5a94985b41da135229d0d9d57b80edad49d5d384d06a4e496291adb75c8be35
Have you been able to use the function swapExactTokensForETH ? Thanks

How do you calculate the amountOut? I see that it is bigger than amountInMax in your transaction.
You can try to use swapExactTokensForETHSupportingFeeOnTransferTokens and specify amountOutMin to 1. This will execute something like sell on the market price. Otherwise you can try to get the current market price and then specify amountOutMin to be calculated with the price you want to sell for.

1 Like

When using ‘swapExactETHForTokens’ I did check the market price for WBNB ( and adjusted it with some tolerance ). When using ‘swapExactTokensForETH’, I did try values manually. I also tried your suggestion with ‘swapExactTokensForETHSupportingFeeOnTransferTokens’ and amountOutMin = 1. I again got the same error ‘Error: Transaction has been reverted by the EVM’

Sorry if this will sound like a beginner question, but I can’t find an easy way to debug this. I’ve tried within Remix, but no luck. Do I need to use truffle to debug a transaction like this? Thanks so much

Send the same txn but using the PancakeSwap UI interface, then once the txn is confirmed, analyze the gas, gas limit & input data of that txn. Try to use that same data in your code. You might find my sample code here helpful: https://github.com/fkochan/swapsushis/blob/master/swapexample/index.js

2 Likes

Thank you. That was very useful. I did check the data and try to reincorporate it in my code after decoding it using abiDecoder for Node.js. I’m still looking into what I am doing wrong. Thanks also for your git link. By the way, had you tried yourself to use swapExactTokensForETH ?

1 Like

I haven’t tried it but it should be fairly similar. Are you getting the same error? If you still cannot get it, post your full code again and we’ll take a look.

1 Like

How do you calculate the deadline? Do you use 20 mins tolerance? Your transaction look ok. Only from this I don’t see anything wrong with it.
I also debug by first executing the transaction through the UI and then posting the same arguments and data from the web3 library.

1 Like

Yes, I do use 20 mins tolerance.
Here’s my code to sell 1 USDT and buy a minium amount of 0.03 BNB. I’ve removed obviously the value of pu and pv ( private and public address ).
The account I am using has 1.1 USDT and 0.08 BNB

Now I am getting ‘Error: Returned error: insufficient funds for gas * price + value’
Thanks for your help

var pv = ""
var pu = ""
var Tx = require('ethereumjs-tx').Transaction;
var Web3 = require('web3')
var Common = require('ethereumjs-common').default;

var pancakeSwapAbi = [{"inputs":[{"internalType":"address","name":"_factory","type":"address"},{"internalType":"address","name":"_WETH","type":"address"}],"stateMutability":"nonpayable","type":"constructor"},{"inputs":[],"name":"WETH","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"tokenA","type":"address"},{"internalType":"address","name":"tokenB","type":"address"},{"internalType":"uint256","name":"amountADesired","type":"uint256"},{"internalType":"uint256","name":"amountBDesired","type":"uint256"},{"internalType":"uint256","name":"amountAMin","type":"uint256"},{"internalType":"uint256","name":"amountBMin","type":"uint256"},{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"deadline","type":"uint256"}],"name":"addLiquidity","outputs":[{"internalType":"uint256","name":"amountA","type":"uint256"},{"internalType":"uint256","name":"amountB","type":"uint256"},{"internalType":"uint256","name":"liquidity","type":"uint256"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountTokenDesired","type":"uint256"},{"internalType":"uint256","name":"amountTokenMin","type":"uint256"},{"internalType":"uint256","name":"amountETHMin","type":"uint256"},{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"deadline","type":"uint256"}],"name":"addLiquidityETH","outputs":[{"internalType":"uint256","name":"amountToken","type":"uint256"},{"internalType":"uint256","name":"amountETH","type":"uint256"},{"internalType":"uint256","name":"liquidity","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[],"name":"factory","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"reserveIn","type":"uint256"},{"internalType":"uint256","name":"reserveOut","type":"uint256"}],"name":"getAmountIn","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"pure","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"reserveIn","type":"uint256"},{"internalType":"uint256","name":"reserveOut","type":"uint256"}],"name":"getAmountOut","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"pure","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"}],"name":"getAmountsIn","outputs":[{"internalType":"uint256[]","name":"amounts","type":"uint256[]"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"}],"name":"getAmountsOut","outputs":[{"internalType":"uint256[]","name":"amounts","type":"uint256[]"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountA","type":"uint256"},{"internalType":"uint256","name":"reserveA","type":"uint256"},{"internalType":"uint256","name":"reserveB","type":"uint256"}],"name":"quote","outputs":[{"internalType":"uint256","name":"amountB","type":"uint256"}],"stateMutability":"pure","type":"function"},{"inputs":[{"internalType":"address","name":"tokenA","type":"address"},{"internalType":"address","name":"tokenB","type":"address"},{"internalType":"uint256","name":"liquidity","type":"uint256"},{"internalType":"uint256","name":"amountAMin","type":"uint256"},{"internalType":"uint256","name":"amountBMin","type":"uint256"},{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"deadline","type":"uint256"}],"name":"removeLiquidity","outputs":[{"internalType":"uint256","name":"amountA","type":"uint256"},{"internalType":"uint256","name":"amountB","type":"uint256"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"liquidity","type":"uint256"},{"internalType":"uint256","name":"amountTokenMin","type":"uint256"},{"internalType":"uint256","name":"amountETHMin","type":"uint256"},{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"deadline","type":"uint256"}],"name":"removeLiquidityETH","outputs":[{"internalType":"uint256","name":"amountToken","type":"uint256"},{"internalType":"uint256","name":"amountETH","type":"uint256"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"liquidity","type":"uint256"},{"internalType":"uint256","name":"amountTokenMin","type":"uint256"},{"internalType":"uint256","name":"amountETHMin","type":"uint256"},{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"deadline","type":"uint256"}],"name":"removeLiquidityETHSupportingFeeOnTransferTokens","outputs":[{"internalType":"uint256","name":"amountETH","type":"uint256"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"liquidity","type":"uint256"},{"internalType":"uint256","name":"amountTokenMin","type":"uint256"},{"internalType":"uint256","name":"amountETHMin","type":"uint256"},{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"deadline","type":"uint256"},{"internalType":"bool","name":"approveMax","type":"bool"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"removeLiquidityETHWithPermit","outputs":[{"internalType":"uint256","name":"amountToken","type":"uint256"},{"internalType":"uint256","name":"amountETH","type":"uint256"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"liquidity","type":"uint256"},{"internalType":"uint256","name":"amountTokenMin","type":"uint256"},{"internalType":"uint256","name":"amountETHMin","type":"uint256"},{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"deadline","type":"uint256"},{"internalType":"bool","name":"approveMax","type":"bool"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"removeLiquidityETHWithPermitSupportingFeeOnTransferTokens","outputs":[{"internalType":"uint256","name":"amountETH","type":"uint256"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"tokenA","type":"address"},{"internalType":"address","name":"tokenB","type":"address"},{"internalType":"uint256","name":"liquidity","type":"uint256"},{"internalType":"uint256","name":"amountAMin","type":"uint256"},{"internalType":"uint256","name":"amountBMin","type":"uint256"},{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"deadline","type":"uint256"},{"internalType":"bool","name":"approveMax","type":"bool"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"removeLiquidityWithPermit","outputs":[{"internalType":"uint256","name":"amountA","type":"uint256"},{"internalType":"uint256","name":"amountB","type":"uint256"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"},{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"deadline","type":"uint256"}],"name":"swapETHForExactTokens","outputs":[{"internalType":"uint256[]","name":"amounts","type":"uint256[]"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountOutMin","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"},{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"deadline","type":"uint256"}],"name":"swapExactETHForTokens","outputs":[{"internalType":"uint256[]","name":"amounts","type":"uint256[]"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountOutMin","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"},{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"deadline","type":"uint256"}],"name":"swapExactETHForTokensSupportingFeeOnTransferTokens","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMin","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"},{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"deadline","type":"uint256"}],"name":"swapExactTokensForETH","outputs":[{"internalType":"uint256[]","name":"amounts","type":"uint256[]"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMin","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"},{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"deadline","type":"uint256"}],"name":"swapExactTokensForETHSupportingFeeOnTransferTokens","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMin","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"},{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"deadline","type":"uint256"}],"name":"swapExactTokensForTokens","outputs":[{"internalType":"uint256[]","name":"amounts","type":"uint256[]"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMin","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"},{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"deadline","type":"uint256"}],"name":"swapExactTokensForTokensSupportingFeeOnTransferTokens","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMax","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"},{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"deadline","type":"uint256"}],"name":"swapTokensForExactETH","outputs":[{"internalType":"uint256[]","name":"amounts","type":"uint256[]"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMax","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"},{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"deadline","type":"uint256"}],"name":"swapTokensForExactTokens","outputs":[{"internalType":"uint256[]","name":"amounts","type":"uint256[]"}],"stateMutability":"nonpayable","type":"function"},{"stateMutability":"payable","type":"receive"}]
var pancakeSwapRouterAddress = '0x10ed43c718714eb63d5aa57b78b54704e256024e';
let pancakeSwapContract = pancakeSwapRouterAddress.toLowerCase();

var web3 = new Web3(new Web3.providers.HttpProvider('https://bsc-dataseed.binance.org/'));
var BSC_FORK = Common.forCustomChain(
    'mainnet',
    {
        name: 'Binance Smart Chain Mainnet',
        networkId: 56,
        chainId: 56,
        url: 'https://bsc-dataseed.binance.org/'
    },
    'istanbul',
);
var BNBTokenAddress = "0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c"; //BNB
var USDTokenAddress = "0x55d398326f99059fF775485246999027B3197955"; //USDT
var gasPrice = 5000000000;

async function sellOneUSDTbuyBNB(targetAccount) {
    var privateKey = Buffer.from(targetAccount.privateKey.slice(2), 'hex')  ;
    try {
        var contract = new web3.eth.Contract(pancakeSwapAbi, pancakeSwapRouterAddress, {from: targetAccount.address});
        var data = contract.methods.swapExactTokensForETH(
            web3.utils.toHex((Math.round(10**18)).toString()),
            web3.utils.toHex((Math.round(3*10**15)).toString()),
            [USDTokenAddress,BNBTokenAddress],
            targetAccount.address,
            web3.utils.toHex(Math.round(Date.now()/1000)+60*20),
        );

        var count = await web3.eth.getTransactionCount(targetAccount.address);
        var rawTransaction = {
            "from":targetAccount.address,
            "gasPrice":web3.utils.toHex(gasPrice),
            "gasLimit":web3.utils.toHex(2900000),
            "to":pancakeSwapRouterAddress,
            "value":web3.utils.toHex((Math.round(10**18)).toString()),
            "data":data.encodeABI(),
            "nonce":web3.utils.toHex(count)
        };

        console.log('rawTransaction',rawTransaction);
        var transaction = new Tx(rawTransaction, { 'common': BSC_FORK });
        transaction.sign(privateKey);
        var result = await web3.eth.sendSignedTransaction('0x' + transaction.serialize().toString('hex'));
        return 1;
    } catch (error) {
        console.log(error)
    }
}

var targetAccount = {"address":pu,"privateKey":pv}
var res = sellOneUSDTbuyBNB(targetAccount);


Can you try with smaller amount? Try to sell 0.0001 USDT and if it succeeds then increase the value.
I have also got similar errors when I tried to buy from accounts which didn’t have enough balance.

Also the value of the transaction should be 0 when you sell tokens.

1 Like

I replaced the transaction value with web3.utils.toHex(‘0’) and it works now!
That was the issue! Thanks a lot.

The code above works then with rawTransaction like below:

        var rawTransaction = {
            "from":targetAccount.address,
            "gasPrice":web3.utils.toHex(gasPrice),
            "gasLimit":web3.utils.toHex(2900000),
            "to":pancakeSwapRouterAddress,
            "value":web3.utils.toHex('0'),
            "data":data.encodeABI(),
            "nonce":web3.utils.toHex(count)
        };
1 Like