A BSC memecoin sniper bot watches PancakeSwap and other BSC DEXes for newly-added liquidity pairs, then races to buy a small position before the token pumps or rugs. BSC remains the highest-volume memecoin chain in 2026 — over $1.5B in daily DEX volume according to DefiLlama , with hundreds of new tokens listed every week. Building a sniper requires three things: a mempool or events listener for new pairs, a swap API that handles the BSC decimals gotcha (USDT and USDC are 18 decimals on BSC, not 6), and a slippage-tolerant executor that retries on revert. Using swapapi.dev removes the auth and rate-limit pain — one GET request per quote, no API key, supports BSC (chain ID 56 ) natively. This guide walks through a production-quality BSC sniper in TypeScript using viem and swapapi.dev. By the end you'll have a ~250-line Bun script that detects new pairs, checks safety conditions, and executes with the slippage retry pattern.…