Eureka moves the heavy thinking backstage. Ethereum gets the result.

Eureka Labs announced BEX on Ethereum mainnet on 29 October. Its builder runs read-only computation against a block as it is assembled, then uses the result in an on-chain transaction. The large computation allowance belongs to the builder’s off-chain work; it is not a rise in Ethereum’s block gas limit.

The documentation separates a request into compute and execute stages. The compute stage reads evolving block state without changing it. The execute stage is the transaction that can act on the result in the same block. That can be useful for strategies whose correct action depends on the latest balance, price or position size.

Published production limits list 500 million gas for compute and two million for the on-chain execution. Developers are told to consult the capabilities endpoint for authoritative current limits. Access is restricted: most BEX methods require an allowlisted signing address, rather than being available to any anonymous caller.

The launch’s no-cost-computation claim also needs its boundary. The documentation says an execution is included only when it increases the builder’s coinbase balance, with payment exceeding its gas fee. Heavy calculations staying off-chain does not mean every resulting transaction is free.

Eureka says a second version planned for 2027 will add live external data and WebAssembly-language support. Those are future features in the announcement. The present development is programmable computation within this builder’s workflow, with its own access and inclusion conditions, rather than a universal change to Ethereum.