Ethereum Mempool is a bug waiting hall for all transactions on the Ethereum network that are to be validated by the miners. It contains all data about transactions: transaction hash, sender address, receiver address, gas price, and gas limit. You may also imagine it as a queue where transactions are lined up one by one as they appeared in the network.
The main task of all these transactions is to be included in the next block generated in the network and validated by miners. When you send a transaction on Ethereum, your data will be added to the mempool first, and only after validation you’ll get the transaction added to the new block.
Let’s have a closer look at the data that mempool contains and what roles it plays. The gas limit and gas price determine the transaction fee. It shows how much the sender may pay for the transaction included in the following block. Miners review the gas price of all transactions and prioritize them: the higher the gas price, the higher chance to be included in the next block.
The nature of a mempool looks like a flow: the new transactions are added, and the confirmed transactions are deleted. Also, the transactions not included in a block for a long time may be deleted from the mempool and must be resent to the network.
Everything starts when a user creates a transaction. Then they broadcast it to the network with all complementary parameters, such as the sender and recipient addresses, the amount being sent, the transaction fee, etc.
Nodes of the network check if the request is valid. After checking up, if everything is OK, it will be added to the mempool.
Miners hand-pick transactions they plan to include in the following block they’re mining. They are interested in selecting transactions with higher fees to increase the total block reward they get. Other transactions stay on hold until they drop off the mempool because of the timeout or miners pick them into the block. Then a user should resend the transaction again to the mempool.
When miners include the transactions pool into the block and mine the block, all included requests are confirmed and deleted from the mempool of all nodes.
Set up the proper transaction fee corresponding to the current mempool state. You can check it using block explorers like Blockchair or other third-party services.
Increase the transaction fee to be higher than minimal/medium values. If you can pay more for your transaction, speed up its confirmation process by paying the higher transaction fee.
Consider Bitcoin transactions accelerator services (e.g., ViaBTC, BTC.com, or F2Pool) to increase the chances of being confirmed faster.
Use the RBF (Replace-by-Fee) feature to increase the fee of an unconfirmed transaction. You may stumble upon Electrum which supports RBF.
Use the CPFP (Child-Pays-for-Parent) technique to use the unconfirmed outputs of a delayed transaction as the inputs for a new transaction with a higher fee. This can force miners to prioritize both the new and the old transactions. For example, Bitcoin Core supports this feature.
To access a mempool, you can connect to the full node with a copy of the blockchain that constantly listens for new requests. This way might be tricky for beginners, as running a full node requires significant computing resources and the skills of a Web3 developer. However, it provides the highest level of control and privacy over network data.
There are a few other ways to access the mempool you might try:
Blockchain explorers. For example, Etherscan offers real-time access to the Ethereum Mempool. Visitors can view streams of pending transactions, sort them by various metrics, and monitor the overall network's activity.
Blockchain APIs: with a Dysnix mempool service, you get access to the network, including the Mempool. These APIs provide easy-to-use endpoints for many processes like retrieving transaction data, sending transactions, and interacting with smart contracts.
The main goal of the ETH mempool is to organize the process of receiving, sorting, and validating created transactions in the most straightforward manner. Miners can’t work without the mempool Ethereum generates, as they prioritize transactions based on the gas price for processing using mempool. It also prevents double-spending and avoids conflicting transactions.
Aside from transaction processing, the mempool conducts fee estimation. Based on the time needed to confirm the transaction and the current state of the mempool, the fee estimation algorithms set the appropriate gas fee for a transaction.
Also, mempool is an indicator of network health. The bigger mempool, the longer it takes to validate the transaction, the more extensive congestion is, and the worse the overall state is.
Another exciting use for the mempool is block exploration. Web3 developers and data scientists are particularly interested in this feature: they can analyze the content of transactions before they are validated to study the behavior and tendencies inside the mempool and Ethereum in general.
In general, mempool is like an open wild market where transaction fees are the main exchange interest. The miners and users are the two types of players here. Miners are interested in validating the block with the highest total transaction MEV sum in the end. Users want their transactions confirmed in the following block by offering the highest possible transaction fee.
Mempool works as a “supply and demand” mechanism. When the demand for block space (number of requests to be confirmed) exceeds the supply (the number of transactions that fit in a block), miners select transactions with higher fees.
Mempool is also a “fee thermometer” and a “fee clock” for transactions. To avoid the situation of frequent transaction denial because of low fees, many services implement fee estimation algorithms that analyze the current state of the mempool and predetermine a lower level of fee for the transaction. If the mempool is overflowed with transactions with high fees, even the most expensive of them will take time to be confirmed.
You can speed up an Ethereum transaction based on the general principles described in the previous point. Also, you might try other specific technics:
Cancel and resend the transaction: If you see that your request stays on hold for a long time, you can delete and resubmit it. But if your old transaction was partially executed, you will most likely lose some of the gas fees you’ve paid.
Change the tool you use. For example, MetaMask allows you to increase the gas prices of a pending transaction. If your current digital purse doesn’t have this function, you’ll need to transfer your funds to the one that has.
To read the mempool, you should directly access blockchain explorers or the fully updated node. There’s no specific mempool provider that will help you to read its data. With blockchain explorers, you can review the pending transactions, their gas price, sender and receiver address, and transaction hash. Also, they can help to navigate and utilize the data of a mempool. The step-by-step instructions on how to read mempool using other methods are the following:
Access the mempool with the help of a command sent to the node.
Review the mempool data: the transaction ID, fee rate, transaction size, inputs and outputs, and the time the transaction was received.
Analyze the data: The fee rate is the most important piece of data you might be interested in.
Monitor the mempool to see the current state and edit your transaction fees accordingly.
Use a mempool visualization tool if you need to access this data constantly and make decisions quickly.