mev-boost-relay (Flashbots)

MEV-Boost is a validator sidecar that sources blocks from a competitive marketplace of builders and relays under proposer-builder separation. Validator operators run it alongside their consensus client to receive externally built blocks.

rbuilder is a Rust MEV-Boost block builder that constructs blocks and submits them to relays. Teams that build blocks run it directly or fork it as the base for their own builder.

rollup-boost is a sidecar for OP Stack sequencers that adds MEV-Boost style external block building to a rollup. Sequencer operators run it when blocks should come from outside builders.