Builder (MEV)
A specialized participant that constructs an optimized block of transactions, competing to offer validators the most valuable block to propose.
A builder, in the MEV (Maximal Extractable Value) context, is a specialized participant that constructs a complete, optimized block of transactions — selecting, ordering, and bundling them to capture available MEV (see Kaavon's "Maximal Extractable Value" glossary definition) — then offers that constructed block to a validator for inclusion.
Builders compete against each other to construct the most valuable possible block, and bid for a validator to actually propose it, which is the economic arrangement proposer-builder separation (see Kaavon's "Proposer-Builder Separation (PBS)" glossary definition) formalizes.
Examples
- Multiple builders compete to construct the most valuable possible block, with the winning builder's block ultimately proposed by a validator.
- A builder's role is specifically to construct and optimize a block's contents, separate from a validator's role of actually proposing it to the network.
Learn more
Maximal Extractable Value
Read the Maximal Extractable Value glossary definition
Proposer-Builder Separation (PBS)
Read the Proposer-Builder Separation (PBS) glossary definition
Backrunning
Read the Backrunning glossary definition
Inclusion List
Read the Inclusion List glossary definition