Nodes are the computers that collectively keep a blockchain running. Each one runs software implementing the network's rules, and together they store transaction history, check that new transactions and blocks follow those rules, and pass valid data on to other nodes. Anyone with the right software and enough storage or bandwidth can typically run one. Some node operators run this software on dedicated hardware at home, while others use rented servers, and the choice mainly affects convenience and cost rather than the fundamental role the node plays.
Not all nodes do the same amount of work. A full node keeps a complete copy of the blockchain and independently checks every rule for itself, without needing to trust any other participant. A light, or lightweight, node stores less data and relies on full nodes for some information, trading a degree of independent verification for lower hardware and bandwidth requirements.
The number and geographic spread of nodes, and how independently they are run, is a big part of what makes a blockchain decentralised in practice rather than just in theory. A network with very few nodes, or with nodes concentrated among a small number of operators, is more vulnerable to disruption or collusion than one with a large, diverse set of independently run nodes. This is one reason projects and communities often encourage a broad base of independent node operators, rather than relying on a small handful of large providers.
Key takeaways
- A node is a computer running blockchain software that helps store, verify, and relay network data.
- A full node independently checks that transactions and blocks follow the network's rules, without needing to trust anyone else.
- A large, diverse, widely distributed set of nodes is a key part of what makes a blockchain decentralised.
Node — frequently asked questions
Do I need to run my own node to use crypto?
No. Most wallets and apps connect to nodes run by someone else. Running a personal node is optional, but it can increase privacy and independence, since you are not relying on a third party's view of the network.
What is the difference between a full node and a light node?
A full node stores the entire blockchain and verifies every rule independently. A light node stores less data and depends on full nodes for parts of that verification, which reduces hardware requirements at the cost of some independence.
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