Blockchain

Blockchain Node

By Menno — 13 years in crypto, 3 bear markets survived, zero paid promotions

Last updated: March 2026

A blockchain node is a computer that participates in a blockchain network by storing a copy of the ledger, validating transactions, and communicating with other nodes. Nodes collectively maintain the network's decentralization and trustlessness.

Nodes are the physical infrastructure that makes decentralized blockchains real. Every node stores a copy of the blockchain's transaction history and uses the network's consensus rules to independently verify new blocks and transactions. There's no central server — the blockchain 'lives' collectively across all nodes simultaneously. Bitcoin and Ethereum each have tens of thousands of nodes globally, making them extraordinarily difficult to shut down or censor.

There are several types of nodes with different resource requirements. Full nodes download and independently verify every block and transaction since genesis. An Ethereum full node requires roughly 1–2 TB of storage (fast SSD required). Light nodes (used by most wallets) download only block headers and query full nodes for specific data — much lighter but require trusting that full nodes are honest. Archive nodes store the complete history of all states at every block, requiring 10+ TB, but are necessary for historical data queries (used by Etherscan, block explorers, analytics services).

Running your own node provides maximum trustlessness — you verify everything yourself rather than relying on third-party RPC providers like Infura or Alchemy. During the 2023 Ethereum Infura outage, users who ran their own nodes were unaffected while users relying on Infura temporarily couldn't interact with the blockchain through MetaMask. For DeFi traders, frontrunners, and MEV (Maximal Extractable Value) searchers, running their own nodes reduces latency and provides competitive advantages. Node software options include Geth, Besu, Nethermind, and Erigon for Ethereum execution; Prysm, Lighthouse, Teku for consensus.

Frequently Asked Questions

Do I need to run a node to use crypto?

No. Most users rely on wallet apps (MetaMask, Coinbase Wallet) that connect to third-party RPC providers. But running your own node provides maximum security and privacy — your transactions don't get logged by Infura or Alchemy, and you verify everything yourself. For high-value users, self-operated nodes are best practice.

How many nodes does Bitcoin have?

Bitcoin has approximately 18,000–20,000 reachable full nodes as of 2025, with many more private (non-listening) nodes behind firewalls. Ethereum has roughly 7,000–9,000 reachable execution nodes. These numbers have been relatively stable over the years, though the actual number of running nodes is likely much higher than the reachable count.

Related Terms

Blockchain

A blockchain is a distributed, append-only database where data is organized into linked blocks and secured by cryptography. Once recorded, transactions cannot be altered — making it a trustless, permanent public ledger.

Decentralization

Decentralization in blockchain means distributing control across many independent participants rather than a single entity. It prevents censorship, single points of failure, and unauthorized control — at the cost of speed and efficiency.

Consensus Mechanism

A consensus mechanism is the method a blockchain uses to achieve agreement among distributed nodes on the valid state of the ledger. The two dominant mechanisms are Proof of Work (Bitcoin) and Proof of Stake (Ethereum, Solana).

Validator

A validator is a node that participates in a proof-of-stake blockchain by staking collateral, proposing new blocks, and voting to confirm the chain's state. Validators earn rewards for honest participation and face slashing penalties for misbehavior.