What is a Bitcoin node?
A Bitcoin node is a computer running Bitcoin software and communicating with other computers in the network. It does not have to be a data center: a personal computer running suitable software can be a node, too.
Some nodes independently check every Bitcoin consensus rule. These are called full nodes. Lighter ways of connecting to the network also exist, but they rely more heavily on other computers for information.
What does a full node verify?
A full node does not accept a transaction just because somebody sent it. Among other checks, it verifies the transaction format, the required digital signatures and that the bitcoin being spent have not already been spent.
When it receives a block, it checks its Proof of Work, the transactions it contains and the other protocol rules, including limits on the creation of new bitcoin. If the block breaks the rules the node enforces, it rejects it.
That is independent verification: a full node does not need to trust a miner, a company or another node to determine whether a block is valid.
For more about the structure of a block, read how Bitcoin’s blockchain works.
In under a minute, watch how transactions form blocks and build the blockchain.
What is the difference between miners and nodes?
Miners collect transactions into candidate blocks and compete through Proof of Work to propose the next block.
Full nodes verify whether a proposed block satisfies the rules they enforce. Finding valid Proof of Work is not enough when the block contains invalid transactions or violates another rule.
In simple words: miners propose; full nodes verify. A miner may also run a node, but you do not need to mine to operate a full node.
Also read how Bitcoin mining works or watch the short video “What do Bitcoin miners actually do?”.
How do nodes communicate?
Bitcoin is a peer-to-peer network: computers connect to other computers without relying on one central server to relay every transaction.
When a node learns about a transaction or block, it can check it and relay it to peers according to its policy. That is how information spreads through the network.
Nodes do not all vote inside a central committee. Each node applies its own validation rules and decides what it accepts.
Why do nodes matter for decentralization?
If one central computer decided which transactions were valid, everyone else would have to trust its operator.
Full nodes make Bitcoin different: many independent participants can enforce the rules for themselves. That means a miner’s computing power does not by itself grant permission to change Bitcoin’s supply or create invalid coins.
Bitcoin’s security comes from the combination of consensus rules, independent verification, peer-to-peer communication and Proof of Work.
Watch our Short about who controls Bitcoin.
Do you need to run your own Bitcoin node?
No. You can receive and send bitcoin with a regular wallet without operating your own full node. Many wallets rely on their own servers or other services for transaction information.
But connecting your wallet to your own node lets you verify more information independently. Depending on the setup, this can also improve your privacy.
Running a node does not pay you a mining reward simply for being online. Its main benefit is independent verification.
To understand how wallets relate to the network, read where your bitcoins are.
What is a pruned Bitcoin node?
A pruned full node verifies blocks and transactions using the same consensus rules as a full node that stores all historical block data. After validation, it can delete older block files to save disk space.
This does not mean skipping the checks. It does mean that the node cannot serve all historical blocks to other peers, and some tasks such as rescanning an old wallet have limitations.
For people who want to verify Bitcoin themselves without storing a huge block archive, pruning can be a practical option.
Bitcoin nodes in simple words
Bitcoin does not depend on one company deciding which block is valid. Miners propose blocks, while full nodes independently enforce the rules.
You do not need your own node to start using Bitcoin. But the ability to verify rather than simply trust is one of Bitcoin’s most important ideas.