A committee of 512 votes on the payload

Mike Neuder posted a distillation of enshrined proposer-builder separation on 24 August, covering the form it now takes in EIP-7732 and scheduled for the Glamsterdam hardfork. The split it enshrines already exists in practice through MEV-boost; what changes is that the protocol stops pretending otherwise.

The slot, redrawn

• t=0, the proposer publishes a beacon block containing a signed bid and no transactions.
• t=3, the attestation committee votes on the beacon block.
• t=6, the builder publishes the execution payload, having watched the attestation weight accumulate.
• t=9, a Payload Timeliness Committee votes on whether the payload was actually available.

That committee has 512 members, against roughly 30,000 attesters in the ordinary committee. It exists to answer one narrow question, whether the payload showed up in time, and it is deliberately small enough to answer it quickly.

What builders become

Builders become staked participants in the protocol, depositing a minimum of 1 ETH. That makes trustless payment possible: the consensus layer can debit a builder's stake and credit the proposer directly, rather than relying on an execution-layer transaction the way MEV-boost does today. The post keeps both paths, trustless payments through the consensus layer and trusted payments through the current model.

The distribution that shapes the market

Neuder cites MEV data from the first six months of 2026: the top 0.1% of slots account for roughly a quarter of all MEV, concentrated in blocks worth hundreds of ETH. Almost all slots are worth very little and a handful are worth a great deal.

That is why the payment mechanism gets this much design attention. A system where the value is evenly spread can tolerate a sloppy settlement path. A system where one slot in a thousand carries a quarter of the money cannot, because that is precisely the slot where somebody will be tempted to test what happens if the payload never arrives.