Marek Moraczyński is the Head of Blockchain Engineering at Nethermind, where he leads the execution client development team. He graduated from Warsaw University of Technology with expertise in systems programming and network protocols, and has been working in blockchain infrastructure for over seven years. At Nethermind, Marek led the implementation of The Merge, Ethereum's historic transition to proof-of-stake, and has co-authored multiple EIPs for the Fusaka upgrade. He's particularly focused on history expiry solutions that reduce node storage requirements by over 80%, making it more feasible for individuals to run full nodes. His technical leadership has helped position Nethermind as one of the fastest Ethereum execution clients while maintaining his commitment to client diversity as essential for network resilience. Marek is an active participant in Ethereum core developer calls and frequently shares insights on protocol improvements with the broader community.