Node
Computer storing a copy of the blockchain and participating in transaction verification.
A node is a computer that is part of the blockchain network — stores a copy of the blockchain and communicates with other nodes.
Types of nodes:
1. Full node • Stores entire blockchain (BTC: ~600GB, ETH: ~1TB+) • Independently verifies every transaction • Most important for decentralization — each full node is autonomous
2. Light node (SPV) • Stores only block headers, not full blockchain • Verifies transactions with minimal data • Used by mobile wallets
3. Mining node (Bitcoin) • Full node + GPU/ASIC for mining • Competition for right to create new block
4. Validator node (Ethereum PoS) • Requires 32 ETH locked • Proposes and verifies blocks • Rewarded with ETH, penalized with slashing for errors
5. Archive node • Stores entire network state through full history • Used by blockchain explorers and analytics platforms
Why run a node: