celestia-node is a Go implementation of Celestia's data availability (DA) node, supporting Bridge, Light, and Full node types. It ingests blocks from a Celestia consensus network (CometBFT), erasure-codes them into Extended Data Squares (EDS), and makes shares available via libp2p-based protocols (Shwap/Shrex, Bitswap). Light nodes perform Data Availability Sampling (DAS) to probabilistically verify block availability without downloading full blocks. The system exposes a JSON-RPC API for blob submission/retrieval, header sync, state queries, and node administration. Architecturally, the application is built with Uber FX dependency injection, composing modules for P2P networking (libp2p with DHT discovery), share exchange, header syncing, state/tx client (gRPC to core), blob service, DAS coordinator, EDS store (file-based with caching), and telemetry (OpenTelemetry, Prometheus). It includes a comprehensive test suite with in-memory mock networks and Docker-based end-to-end tests. While primarily a production blockchain node, it also serves as a reference implementation for Celestia's research protocols (NMT-based proofs, erasure coding, DAS).