MEV in staking: how block building affects validator rewards
Validators on proof-of-stake chains don't just earn base rewards for proposing blocks. They can also capture extra value by ordering transactions in the most profitable way. That extra value is called MEV - maximal extractable value.
MEV is not a fixed fee. It depends on what users are willing to pay for priority. Arbitrage bots pay heavily. So do liquidators. A validator who sequences those transactions optimally can earn significantly more than one who doesn't. This creates a problem. Validators were originally supposed to order transactions fairly - by timestamp or by gas price. But the market found better ways.
The MEV-Boost Architecture
The dominant solution today is MEV-Boost. It works like a marketplace. Builders compete to construct the most valuable block. They send these blocks to relays. Relays check them for validity and pass the best ones to validators. The validator picks the most profitable block and proposes it. The builder pays. The relay takes a cut. The validator gets the rest.
This is not a simple system. It has three distinct actors.
Builders write software that scans the mempool for profitable opportunities. They bundle transactions into block templates. They bid for inclusion. Some builders are professional firms. Some are solo operators with good code.
Relays act as gatekeepers. They verify that builders aren't cheating - that the block is valid and the payment is real. Relays also censor. They can refuse blocks that contain certain transactions. This is where the ethical questions start.
Validators choose among the blocks that relays deliver. They have no say in which transactions are inside. They only see the fee they will receive.
Relay Selection Trade-Offs
A validator can connect to multiple relays. More relays mean more block options. More options mean higher potential MEV. But relays are not neutral infrastructure. Some are run by well-known staking services. Others are anonymous. A relay can go offline. A relay can lie about payment. A relay can censor transactions you would have included if you were building the block yourself. The trade-off is simple. More relays increase your MEV capture. They also increase your risk and your dependence on third parties.
Some validators run their own relays. That eliminates censorship risk but requires engineering skill. Most don't. They pick a few trusted relays and hope the system works.
The Ethical Debate
MEV is a feature or a bug depending on who you ask. It makes validators more profitable. That attracts more capital to staking. That strengthens network security. But it also extracts value from ordinary users. Every time a swap is front-run or a liquidation is stolen, someone pays more than they should. That user might be a retail trader. It could be a DeFi protocol. The profits flow to validators and builders rather than the people who created the value.
There is no consensus. Some protocols try to capture MEV themselves. Others try to burn it. Most just accept it and optimize for yield.
Fee Recipient Configuration
To receive MEV at all, a validator must configure a fee recipient address. This address is where the builder sends the additional payment. Without it, the block proposal earns only the base reward. The configuration is simple. It is one field in the validator client software. But getting it wrong costs money. A mistaken address means the MEV goes to someone else.
This is not a theoretical risk. It happens. Validators forget to set it. Validators change clients and don't re-check. The builder sends the payment to the wrong place and nobody can reverse it.
What this means for validators
MEV is not optional anymore. If you run a validator and ignore MEV-Boost, you are leaving money on the table. Your rewards will be lower than every other validator on the network. But joining the MEV market means trusting relays. It means accepting that some transactions will be censored on your behalf. It means configuring software correctly and monitoring it constantly.
The dollar figures depend on network conditions. They change hourly. As of August 31, 2026, no onchain pair was found for badluckbaby.site, so no specific MEV estimate is available for this site's readers. The general principle holds: validators who participate capture more value than those who don't. How much more depends on competition, network activity, and the relay choices you make.
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