Block Builder Role

Definition ∞ The Block Builder Role refers to the function of assembling transactions into a valid block structure for a blockchain. This participant collects pending transactions from a mempool and orders them according to specific criteria, often prioritizing those with higher fees. The builder then proposes this constructed block to a validator for inclusion in the chain. This role is fundamental to transaction processing and network operation.
Context ∞ The block builder role is central to the discussion surrounding Maximum Extractable Value (MEV) in proof-of-stake blockchains, where builders compete to create the most profitable blocks. Debates around fair ordering and potential centralization risks associated with this role are ongoing. Future protocol upgrades often aim to decentralize or mitigate adverse effects of block construction.