A node (node) is any computer connected to a cryptocurrency network and interacting with other participants under the shared rules of the protocol. The collection of nodes forms a decentralized infrastructure in which there is no single central server: the data is distributed across many independent nodes around the world.

Nodes receive and transmit information about transactions and blocks, and also check them for compliance with the network rules. If a transaction violates the protocol — for example, it contains an attempt to spend nonexistent funds — the nodes reject it. Because verification is carried out by many independent participants, it is practically impossible to falsify the transaction history or push through an invalid transaction.

Types of nodes

• Full nodes — store a complete copy of the blockchain and independently verify all the rules.
• Light (lightweight) nodes — store only part of the data and rely on full nodes.
• Nodes with special functions that take part in consensus or routing.

The more independent full nodes there are in a network, the higher its resilience and decentralization. That is why running your own node is considered a contribution to the reliability and security of the entire ecosystem.