How to Access the Ethereum Mempool: Streaming Pending Transactions From a Co-located Node

Every transaction spends a moment in limbo between “broadcast” and “mined”. That waiting room is the mempool, and it is where a lot of the interesting work in Ethereum happens: a searcher spots an arbitrage before it lands, a bot front-runs a large swap, a liquidation watcher sees the transaction that will tip a position underwater. If you want to act on a transaction before it is final, you have to read the mempool.

Every Ethereum RPC call travels over a transport, and the transport you pick sets a floor on how fast that call can ever be. For a wallet showing a balance, the difference is invisible. For an arbitrage bot that reads a price and decides whether to act before the next block, it is the whole game. This post compares the three transports your node speaks, HTTP, WebSocket, and IPC, explains where their latency comes from, and gives you a benchmark you can run to see the gap on your own setup.