Nethermind
Nethermind, founded in 2017 by Tomasz Stanczak and Demetrios Skalkotos in London, builds Ethereum execution client infrastructure and broader protocol tooling. Its flagship Nethermind client, written in .NET, runs significant share of Ethereum nodes, supporting staking, syncing and validator operations alongside contributions to research, formal verification and developer libraries like Warp for Starknet. Beyond the client, Nethermind provides audits, MEV research and data services used by foundations and enterprises deploying Ethereum infrastructure globally. Headquartered in London with teams across the UK, Poland and globally remote, Nethermind is backed by ecosystem grants and service revenue. The team champions client diversity for network resilience and decentralization. Expect an engineering-focused culture that values open-source stewardship, low-level systems craft and meticulous reliability for production Ethereum nodes.