BuilderNet

BuilderNet is an Ethereum block-building network started in November 2024 by Flashbots, Beaverbuild and Nethermind. It addresses block building being captured by a few searchers and orderflow deals: exclusive arrangements buy priority, ordinary transactions are pushed back, and MEV concentrates among a handful of participants.

Several operators each run an rbuilder instance, share orderflow and coordinate bids. Nodes run inside TDX trusted execution environments where operators cannot see transaction contents and can only assemble according to rules, and orderflow providers verify images through attestation. The share of block value attributable to a given flow is returned to its provider under an open-source refund rule. The network produced its first mainnet block on 12 November 2024, and in December Flashbots moved all of its block building onto it.