The mempool (short for memory pool) is a place where all unconfirmed transactions in a blockchain are temporarily stored. Think of it as a “waiting room” for transfers that haven’t yet been added to a block.
When you send cryptocurrency, your transaction doesn’t go directly into the blockchain. First, it’s broadcasted to the network and enters the mempool — a temporary queue where it waits until miners include it in a new block.
A Simple Analogy
Imagine an airport. Passengers (transactions) are waiting in a lounge (the mempool), and planes (blocks) take off on a schedule with limited seating. To get on the next flight, a passenger can pay for business class — same goes for transactions: higher fees mean faster processing.
How the Mempool Works — Step by Step
-
Transaction is created
A user initiates a crypto transfer through a wallet or exchange. -
Broadcasted to the network
The transaction spreads across blockchain nodes and enters their mempools. -
Waiting for confirmation
The transaction sits in the mempool, ranked by its fee. Higher fees = higher priority. -
Picked by miners
Miners select transactions from the mempool to include in the next block. They prefer those with higher fees, since that’s how they get paid.
Why Should You Care?
- Understanding how the mempool works helps you set the right transaction fee.
If the network is congested and your fee is too low, your transaction may get delayed for hours or even days.
You can check current mempool activity and fee recommendations on services like: Mempool.space, Blockchain.com, BTCScan.org.
Final Thoughts
The mempool is a key part of how blockchain works. It brings order to transaction processing and gives users a chance to “bid” for faster confirmation. Once you understand it, you’ll be able to send crypto faster and cheaper — and avoid unnecessary delays.