A node is any device that is connected to a blockchain network and runs its software. Nodes are the backbone of a decentralized system: each one knows the network's rules, checks transactions, and passes blocks on to others.
Common types#
- Full node: stores the entire history and verifies everything itself
- Light node: keeps only a small part of the data and relies on other nodes for the rest
- Validator or miner node: takes part in producing and confirming blocks
Why does it matter?#
The more numerous and widely spread the independent nodes are, the more resilient the network is against failure, censorship, and abuse. If a few parties control the nodes, concentration increases.
Example#
It is like multiple copies of a land registry kept in different cities. Each copy is kept by a different person and regularly compared with the others, so no one can alter it alone.
Practical notes#
Many wallets and apps connect to third-party nodes (RPC providers). This means you may unintentionally depend on a centralized service. If privacy or independence matters to you, you can run your own node, but it requires storage space, bandwidth, and technical knowledge. Never enter your private key in the settings of an unknown node or service.