What is a node?
- Author
- CRYPTO PORT Editorial
- Published
- Updated
- Reading time
- 4 min
In short
A node is a computer running blockchain software and taking part in the network. It receives transactions and blocks, checks them against the rules itself, and passes them on. Having nodes spread worldwide is what removes the need for a central operator.
Key points
- Holds a copy of the ledger and rejects invalid data itself
- A full node validates the entire history
- Miners and validators are specialised nodes
- Most wallets connect to someone else's node
Definition
A machine running an implementation of the blockchain protocol that validates and relays transactions and blocks.
A full node downloads the entire history and checks every transaction against the rules itself. It does not take anyone's word that a block is valid — it decides using its own copy of the rules. That accumulated distrust is why invalid blocks do not propagate.
Mining and validating nodes add block production on top of that verification role. Many nodes never produce blocks and only verify and relay; the more of those there are, the harder it is to push through a rule change.
Most phone wallets do not run a full node. They query a provider's node for balances and history. That is convenient, but the provider can observe which addresses you query and from where — a privacy property worth knowing about.
Watch out for
- · Running a full node means ongoing storage and bandwidth costs
- · A wallet querying someone else's node is trusting the answers it gets back