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Allows sniping pool creation events for Uniswap V2-styled routers in under 250 LOC. Monitors UniswapV2Factory for PairCreated events, verifies that one of the tokens of pair matches your desired sniping tokens, and automatically submits a purchase transaction (with initial token for route === base chain token, eg. ETH or Matic).

This repo is a proof-of-concept implementation of sniping the Klima pool launch on Sushiswap Router V2 — Polygon. If you do not want to test on Polygon Mainnet, do not apply the postinstall patch and change src/sniper.ts:L73 to desired network.

Credits: @joshstevens19 for simple-uniswap-sdk


# Clone repo
git clone

# Install dependencies
npm install

# Re-run post install (just in case, see issue #1)
npm run postinstall

# Update environment variables
cp .env.sample > .env
vim .env

# Run pool-sniper
npm run start

Local testing

The Polygon mainnet is defined in the sniper code. You can use polygon testnet by turning IS_TESTNET to true in your .env. Please note your RPC_ENDPOINT to be a testnet node.

The easiest way to test locally is:

  1. Deploy a new ERC20 and mint yourself some tokens:
// SPDX-License-Identifier: Unlicense
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/presets/ERC20PresetMinterPauser.sol"; // OZ: ERC20

contract Tester is ERC20 {
    constructor(string memory _name, string memory _symbol) ERC20(_name, _symbol) {
        _mint(msg.sender, 1e18 * 1000);
  1. Copy the deployed address and add to .env
  2. Run the sniper (npm run start)
  3. Create a new UniswapV2-styled pool with deployed ERC20 and base chain asset (eg. ETH/Matic) and watch your sniper pick up the new pool creation


  1. This code is manually tested and unaudited. Proceed with caution.
  2. The sniper does not perform any cost checks. Ideally, you implement a maximum clearing price above which you no longer send a purchase transaction.
  3. This sniper checks for confirmed transactions (and thus, emitted events). For better performance, you can try to watch the mempool for the unconfirmed pool creation transaction, or run the purchase submission on loop and bite the minimal revert cost on Polygon.
  4. In the case where a pool operator adds minimal liquidity to begin and follows it up with more in another block, the sniper will pounce at the opportunity to buy regardless. Use safe slippage measures and add error handling.
  5. Be careful to not purchase a malicious token.




Uniswap V2-styled router new pool sniping in under 250 LOC.