MemPool in Blockchain: How the Transaction Waiting Pool Works

When you send a transaction on the Blockchain, it doesn’t instantly get recorded in the network’s ledger. Instead, it first goes into a special storage area — the mempool (Memory Pool). This is one of the most important but often misunderstood concepts in cryptography. Let’s understand what happens to your money while it waits for confirmation.

Mempool: A Simple Analogy

Imagine a popular restaurant on a Friday night. When you arrive, you don’t immediately sit at a table — you join a queue at the entrance. The waiting buffer is the mempool. Your order (transaction) is recorded, and you’re officially in the list, but you’re not being served yet. You’re waiting for the waiter (Miner) to attend to you.

Here’s another example: in a game, there’s a matchmaking queue. When you click “Start,” you don’t immediately begin playing. You end up in a pool of waiting players. The system scans this pool and forms teams when enough players are available. Similarly, miners scan the mempool and choose which transactions to include in the next block.

But there’s an important detail: if you’re willing to pay more (higher gas fee), you’ll get a better spot in line. A high fee is like giving a generous tip to the waiter. Your transaction moves higher up in the queue.

Technical Aspects of the Mempool

As simple as it sounds, the mempool is actually more complex.

Decentralized Structure. There isn’t a single mempool. Each node in the Blockchain network has its own copy of the mempool. When you send a transaction, it is transmitted from node to node, and each node adds it to its own waiting pool. Nodes constantly synchronize information to keep their mempool versions roughly the same.

Cleaning and Removal. When the mempool overflows (the network is congested), nodes start deleting transactions with the lowest fees. If your gas fee is too low, your transaction may be completely removed from the mempool. This means it will never be processed or added to the Blockchain.

Expiration. Some networks also delete very old transactions that have been waiting for confirmation for a long time. This prevents endless accumulation of outdated requests.

Practical Application: Why Monitor the Mempool

Understanding how the mempool works is practically important for anyone working with cryptocurrency.

When you see the mempool is almost empty, it means the network is free. You can send a transaction with a minimal fee, and it will be processed quickly. The miners are bored and ready to take your order.

If, on the other hand, the mempool is full of thousands of pending transactions, you know: either wait or pay more. It’s like during holidays — you can wait for the congestion to decrease or leave a generous tip to get served sooner.

Many experienced Blockchain users monitor the mempool status before sending large transactions. This helps save on fees and avoid unnecessary delays. Thus, understanding how the mempool works gives you control over your money and allows you to make smarter decisions when working with cryptocurrency.