Node
Also: full node
network · beginner
A computer running Bitcoin software that independently validates every block and transaction against the consensus rules.
A full node downloads and verifies the entire chain. It doesn't trust anyone — not miners, not other nodes. If a block breaks the rules, every node rejects it independently. This is why Bitcoin can have ~20,000 reachable nodes around the world and still agree on a single state: every node checks the same rules against the same data.
Running your own node is the only way to fully self-validate. A wallet pointed at someone else's node is fast and convenient, but you're trusting that node to tell the truth about the chain. For most everyday spending this is fine; for high-value holdings, self-verifying via your own node — even a pruned one running on a Raspberry Pi — is the practice.
Nodes also enforce the rules. When a soft fork or hard fork is proposed, what determines whether it actually happens is whether nodes upgrade to enforce the new rules. Miners produce blocks, but nodes are the ultimate arbiters of validity. "Not your node, not your rules" overstates it slightly, but the kernel is real: a network of independently validating nodes is what keeps Bitcoin's consensus from collapsing into miner discretion.