Ethereum MEV-Boost API
Who actually builds Ethereum's blocks and which relays deliver them — live from the public MEV-Boost relay APIs, no key. Since the Merge most Ethereum validators outsource block construction through MEV-Boost: specialised block builders compete to assemble the most valuable block (capturing MEV — arbitrage, liquidations, sandwiches — plus priority fees), relays act as trusted middlemen between builders and validators, and the validator simply signs the highest-paying block. This builder-and-relay market is one of the most important and most centralised pieces of Ethereum's infrastructure — a handful of builders win the large majority of blocks — so tracking who is winning and how much they pay is core to Ethereum decentralisation and MEV analytics. The builders endpoint ranks block builders by how many of the recent blocks they won, with each builder's block share, the total and average value (in ETH) they paid validators, and a name where the builder's public key is known. The relays endpoint shows each MEV-Boost relay's reach across the major relays (Flashbots, Ultrasound, bloXroute, Agnostic, Aestus, Titan). The blocks endpoint lists the most recent blocks delivered through MEV-Boost, each with its builder, the value paid to the proposer, gas used, transaction count and which relays delivered it. This is the block-building / MEV-Boost cut, the supply side of Ethereum block production — distinct from the blob-space fee market, the execution-gas oracle, the ETH supply/burn feed and the on-chain and DeFi feeds. Values are in ETH; everything is live. Built for Ethereum infrastructure, MEV research, staking and analytics tools.
api.oanor.com/mevboost-api
