Eureka Labs launches BEX execution engine on Ethereum mainnet
Eureka Labs' BEX lets developers run code inside Ethereum's block builder during block assembly, with up to 500M gas per request and no fee without a result.
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CoinShark Newsroom
10/29/20261 min read
TEL AVIV, Oct 29, 2026 — Ethereum block-building company Eureka Labs today launched BEX on Ethereum mainnet, an execution engine that lets developers run their own code inside the block builder while a block is still being assembled.
Instead of submitting a finished transaction, developers send code that executes against the block as it takes shape. If the code finds an opportunity, it places a small transaction into that same block; if it finds nothing, nothing is posted onchain. Eureka says BEX supports up to 500 million gas per request and charges no fee unless the code produces a transaction. According to the company, BEX already handles about 5 million computations per day, with more than 40% of requests exceeding the gas of an entire Ethereum block. Early users are mainly searchers, trading teams that look for and close price gaps between markets.
"A block takes 12 seconds to build, and prices move the whole time," said Marissa Posner, Head of Product at Eureka. CEO Nir Magenheim put the launch in historical context: "Ethereum gave developers smart contracts in 2015. BEX gives them the block itself."
Eureka ties the release to Ethereum's upcoming Glamsterdam upgrade, which includes ePBS, and says its share of Ethereum blocks grew from about 1% to 10% this year. A second version planned for 2027 is set to add live real-world data and support for languages that compile to WebAssembly, such as Rust and Go. The company also plans hands-on workshops next month and an open-source SDK.
Founded in December 2024 and based in Tel Aviv, Eureka Labs builds block-building infrastructure and developer tools for Ethereum.
Source: Chainwire, Eureka Labs