Full node is a type of blockchain node that independently validates blocks and transactions according to the rules of the relevant protocol.

A full node normally stores substantial blockchain data and maintains enough state to validate new transactions and blocks. Some implementations also support archival modes that preserve additional historical information.

Why full nodes are used

Independent validation reduces reliance on external servers when determining which transactions and blocks are valid. A full node can reject data that violates protocol rules even if another participant claims that the data is correct.

Requirements vary by blockchain and can include substantial disk space, fast storage, memory, CPU resources, synchronization time, and network bandwidth.