What is Mempool?

The Mempool (short for Memory Pool) is the mechanism by which cryptocurrency nodes temporarily store unconfirmed transactions. When a customer sends a payment, the transaction is broadcast to the network and sits in the mempool of various nodes until a miner picks it up and includes it in a new block.

For merchants, monitoring the mempool is critical for providing a fast checkout experience. Advanced crypto payment gateways scan the mempool to instantly detect a payment broadcast (known as a Zero-Confirmation or 0-conf transaction), allowing the merchant to update the UI instantly without waiting 10 minutes for a Bitcoin block to be mined.