ethlambda is a minimalist, fast and modular implementation of a Beacon Chain and Lean Chain client, written in Rust.
This book collects the design notes and operator-facing references for ethlambda. It is split into five parts:
- Design describes the shape of a running node: the architecture of its actors, workers and shared storage, and how they are wired together at startup.
- Consensus explains how the Lean Chain advances: the slot and interval structure that schedules every validator duty, the 3SF-mini justification and finalization rules, and the LMD-GHOST fork choice algorithm. These documents are implementation-agnostic; ethlambda-specific behaviour is called out in blockquotes.
- Beacon Chain covers the Ethereum Beacon Chain side: its state transition, the mainnet wire, and the execution layer pairing.
- Operations documents observable surfaces of a running node: Prometheus metrics, checkpoint sync, and the fork choice visualization served by the API.
- Development collects notes for contributors, starting with the spec deviations where ethlambda departs from leanSpec (Lean Chain) or consensus-specs (Beacon Chain).
For build and contribution instructions, see the
README and
CONTRIBUTING.md
in the repository.
Two standalone HTML infographics ship alongside this book and are copied verbatim into the rendered output:
- Telegram: ethlambda group, where we post daily updates; drop by to ask questions or chat about anything Lean-related.
- X (Twitter): @ethlambda_lean for occasional updates.
- Weekly community call: every Friday, streamed live on @class_lambda; the call link is posted on Telegram beforehand.
- Ecosystem coordination: the PQ Interop calls on
ethereum/pmcover cross-client Lean Ethereum work and related updates; the meeting links are posted on each issue.
On the Lean Chain, ethlambda is one of several clients under active development. For comparison and cross-client testing: