Can a Miner Include a Lower-Fee Transaction before a Higher-Fee One?
Yes, a miner can technically include a lower-fee transaction before a higher-fee one, as the protocol does not enforce a strict fee-based ordering. However, it is economically irrational for a profit-maximizing miner to do so when block space is scarce.
In a congested network, a miner's software is typically configured to prioritize the highest fee-per-byte to maximize revenue. The only exceptions might be due to a bug, a custom or altruistic policy, or if the miner is optimizing for a factor other than immediate fee revenue, such as Maximal Extractable Value (MEV).
Glossar
Maximal Extractable Value
Concept ⎊ Maximal Extractable Value, or MEV, refers to the profit that miners or validators can extract by strategically reordering, censoring, or inserting transactions within a block.
Fee
Charge ⎊ A fee within cryptocurrency, options, and derivatives represents a cost associated with executing a trade, accessing a platform, or maintaining a position, directly impacting net profitability and requiring precise quantification for strategy backtesting.