Full node
ProtocolThis term is part of the Bitcoin glossary — See all terms
A full node downloads and checks every block and transaction from the very first one, enforcing Bitcoin's rules on its own instead of trusting others.
The Bitcoin motto is "don't trust, verify". A full node takes that literally: it starts from the Genesis block of 2009, downloads every block ever mined — all 970,000-plus of them — and re-checks each transaction against the rules before accepting it. Your balance is not a number a company hands you; it is a total your own software computed from the whole history.
That independence is what protects you. If a majority of miners tried to inflate the supply beyond 21 million coins or sneak in a transaction you never signed, your full node would reject their blocks and keep following the honest chain. Running one costs little: expect roughly 700 GB of disk today and a steady internet connection, and you can watch the chain grow block by block on this block explorer while your node syncs.
