A blockchain node is any computer that participates in a blockchain network by maintaining a copy of the ledger and communicating with other participants. Nodes are the backbone of decentralisation: the more independent nodes there are, the harder the network is to censor, attack, or shut down. Different types of node serve different purposes, and running a node is distinct from mining or validating — though miners and validators typically run nodes as part of their role.
Main node types: Full node — downloads and independently verifies every block and transaction against the consensus rules since genesis; does not require trusting anyone else; the gold standard for security; requires significant disk space (Bitcoin full node: ~600 GB+; Ethereum: several TB for archive); Pruned node — a full node that discards old block data after validation to save disk space while still validating current transactions; Archive node — retains all historical state data (e.g. every account balance at every block height), essential for block explorers, analytics platforms, and some DeFi infrastructure; Light node (SPV) — downloads only block headers, not full block data; trusts that other nodes have validated transactions; much lighter resource footprint; used in mobile wallets; Validator/Miner node — full nodes that additionally participate in consensus (proposing and attesting to blocks); require staking (PoS) or hardware (PoW). For most users, relying on a service like Infura or Alchemy means you’re using their nodes. For privacy and sovereignty, running your own full node is the ideal — it means you self-verify every transaction you care about with no third-party trust.
Example: Someone running a Bitcoin full node on a Raspberry Pi at home independently verifies that every BTC transaction since 2009 follows the rules. When they receive a payment, they don’t need to trust any exchange or wallet provider to confirm it’s valid.
Learn more: Bitcoin.org — Running a Full Node
