What is MEV (Miner Extractable Value)? - MEV Explained



August 24, 2022

7 min read

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MEV, often referred to as Miner Extractable Value or Maximal Extractable Value, is the exploitation of blockchain technology describing the practice of altering transaction blocks in one way or another (typically performed by miners) to receive profits. In this article, we will talk about why MEV could be a huge issue for some popular networks, including Ethereum, and what types of MEV attacks are the easiest to come across.

What is MEV?

In a nutshell, MEV could be utilized by users to maximize value from a particular block. The process is often associated with the Ethereum network; however, it does have quite a long history. The first use-case of MEV was initially identified in 2014 by an algorithmic trader who goes by the name Pmcgoohan.

MEV extracted over time

Source: MEV-Explore

Allegedly, Pncgoohan was so excited about the upcoming launch of Ethereum that he decided to make his own analysis of the promising cutting-edge technology. After having carefully studied ETH’s pre-Genesis docs, he realized that the network had a major flaw. According to the trader, by taking hold of the entire transaction and ordering process, miners could try to extract value from blocks without notifying other users. Unfortunately, Pmcgoohan’s warning was left unnoticed as he was ahead of his time.

Since 2019, other experts have backed up Pmcgoohan’s hypothesis by proving that his theoretical suggestion is, indeed, being exploited by users. The practice could potentially lead to unfortunate consequences.

MEV on Ethereum

MEV occurs when miners (validators) or independent users (also known as ‘searchers’) exploit the Ethereum network by reordering, inserting, or censoring transactions within blocks to get additional income. The Proof-of-Work protocol implies that miners are in charge of including, excluding, and ordering all transactions; thus allowing them to control the entire network. It is also worth noting that the term ‘miner extractable value’ will no longer be applicable due to the upcoming Merge of the Ethereum network into a Proof-of-Stake blockchain; therefore it is advised to use ‘maximal extractable value’ instead.

The bug appears when users continuously select transactions with the highest gas price and fees. However, transactions are not required to be ordered depending on their fees, therefore resulting in an irregular stream of revenue, otherwise called MEV.

MEV arbitrage explained

Although theoretically, only miners/validators are capable of exploiting the protocol’s drawback, MEV is currently being largely popularized by stand-alone participants (the so-called ‘searches’). One of the simplest and most well-known MEV opportunities is known to be the DEX arbitrage. In the case that two decentralized exchanges offer a token at different prices, searchers can purchase the token for the lowest price and auction it off on the other exchange for a much higher value.

MEV extracted by protocol

Source: MEV-Explore

Some searchers have special MEV bots that run complex algorithms instead of them to identify the most profitable real-time opportunities within the MEV arbitrage as fast as possible.

While participating in an arbitrage opportunity is a traditional practice in the financial world (normally two separate transactions are necessary to complete the opportunity), it gets more complicated in the world of digital finance. Crypto technology leverages the idea of anonymity and full disclosure, hence why participants can see pending transactions on the public mempool and detect the outcome of the transaction before it is finalized on-chain.

Types of MEV attacks

While MEV attacks could greatly differentiate between each other, let’s take a quick look at some of the most common use-cases.


Front-running is known to be one of the first forms of MEV. The practice implies that bots deliberately look for transactions with the highest gas fees and put them in front of the execution line, completely skipping other pending transactions.


Back-running describes the process of utilizing a MEV bot to get a particular transaction immediately after a pending transaction with the intent of changing market conditions and making a profit.

Sandwich trading

A sandwich attack combines both of the types mentioned above. Widely used to manipulate prices on decentralized exchange platforms, searchers tend to place a particular transaction before and after a victim’s transaction. This can push the unsuspecting user to increase the price of the transaction and allow bots to sell their assets for a higher price.


Liquidators are the type of miners intended to extract MEV from victims by liquidating their loans before the unsuspecting trader is ready to repay the debt and auction off the collateral.

Uncle bandit

Uncle bandit attacks refer to the practice of re-mining previously mined blocks to get the maximum possible arbitrage opportunity and benefit from the protocol’s incentives, which may cause significant instability in the network.

What are the effects of MEV?

Essentially, MEV negatively affects unsuspecting users resulting in a much poor experience at the application layer. What’s more, the practice - done with malicious intent - could also drive up gas fees and cause serious congestion. Overly re-mined blocks may lead to full blockchain re-organization and undermine the integrity of the network resulting in destabilization and eradication of decentralization, security, and usability.

Overall, MEV remains one of the biggest challenges Ethereum and similar networks have to face today, as there is currently hardly any plausible solution to prevent MEV from outweighing traditional block rewards.

However, some experts believe that MEV could be avoided if the community focuses on developing special tools, such as flashbots, which will help make MEV more accessible.

Ethereum blockchain nodes for better profit opportunities

In conclusion, while MEV remains unavoidable for many blockchains, including Ethereum and other similar networks, flashbots have reduced the negative effects of block value extraction on non-miners.

With the help of GetBlock - a Blockchain-as-a-service provider for 40+ networks - users can create flashbots and other products to prevent malicious MEV attacks. Blockchain nodes hosted by GetBlock are easily integratable into your business.

Ethereum nodes are also available for GetBlock clients. The options include Shared and Dedicated nodes, as well as node clusters for ETH.

To integrate Ethereum nodes’ endpoints today please log in to your GetBlock account and choose our shared or dedicated nodes solution.

If you need custom settings, please, reach out to our customer care team.

Final thoughts

Many experts argue that MEV cannot be prevented easily and crypto users need to be aware of the phenomenon. While for some MEV is an opportunity to gain additional profits, others criticize miners for exploiting the ability to collect invisible tax from unsuspecting users. Therefore, the crucial importance of being familiar with MEV as a type of practice is presented in front of all crypto and blockchain enthusiasts. Being prepared for MEV attacks can help prevent network congestion and full destabilization.


How to create a MEV bot?

In order to create a MEV bot, you need to

  1. Get the private keys by using a node provider;
  2. Build the bot (you need a starting code);
  3. Experiment with your bot in action.

Check out this guide on how to build a MEV bot.

What does a MEV bot do?

A MEV bot monitors the blockchain for unfinalized transactions with higher gas fees and trades.

How do you get miner extractable value?

Users (typically miners or searchers) receive MEV from extracting value from unfinalized transactions by changing the order of transactions within blocks based on the profit opportunities.



August 24, 2022

7 min read