Block Builder / Ethereum Protocol Expert JB-4873

The company is building a next-generation block builder that augments Ethereum’s capabilities, unlocks new DeFi primitives, and improves neutrality while making block participation more accessible.

As a Protocol Expert you’ll be the steward of protocol-level systems: you’ll author production-grade Rust services, define how blocks are

constructed and transactions are ordered, own PBS-related integrations, and partner with validators, relays and searchers — directly shaping ordering and inclusion rules, hardening deterministic simulations and safety checks, and driving measurable impact across the Ethereum ecosystem.

What you’ll build:

A production-grade block builder platform and the off-chain infrastructure that powers it: block construction algorithms, secure low-latency builder↔relay communication and bundle handling, deterministic simulation and safety tooling, and rich observability for builder performance and market effects.

Crucially, you will also design and deliver a first-of-its-kind DeFi primitive that depends on our builder’s augmented capabilities — a concrete, production-ready demonstration of the platform’s unique value to users and the wider ecosystem.

Requirements:

Deep PBS / MEV expertise - strong practical knowledge of Proposer-Builder Separation, MEV-Boost architecture, relay ecosystems and timing games.

Ethereum internals - solid understanding of consensus and execution layers (slots/epochs, fork choice, payload delivery) and EVM execution semantics.

At least 7 years of software engineering experience, with at least 3 years focused on blockchain infrastructure or MEV systems.

Production Rust. Proficiency building high-performance, networked services in Rust.

Experience running production, security-sensitive infrastructure with monitoring, testing and on-call responsibilities.

Able to translate protocol tradeoffs into engineering plans and to coordinate across relays, searchers and validators.