Network Architecture: Nodes, Clients, and Sync
How a blockchain network actually runs — full nodes, light clients, archive nodes, propagation, and what it means to "run a node."
12 min · beginner · part of Blockchain: The Trust Machine
What you'll learn
- What Is a Node?
- What Running a Node Actually Looks Like
- Client Diversity and Why It Matters
- How Transactions and Blocks Propagate
- For Deeper Reading
Key terms
- Node
- A computer running blockchain network software. Maintains a copy of the chain, validates new transactions and blocks, and relays them to peers. The basic unit of blockchain infrastructure.
- Full node
- A node that independently validates every block and transaction, maintaining a complete copy of the blockchain. The backbone of decentralization.
- Light client / SPV
- A lightweight node that stores only block headers and verifies transactions via Merkle proofs from full nodes. Mobile wallets are typically light clients.
- Archive node
- A full node that additionally retains all historical state at every block height. Used for historical queries and analytics. Requires significantly more storage than a regular full node.
- Pruned node
- A full node that deletes old block data after validation, retaining only recent blocks. Saves disk space; Bitcoin Core can prune to as little as 5 GB.
- Mempool
- The "memory pool" of unconfirmed transactions waiting to be included in a block. Each node maintains its own mempool, which may differ slightly between nodes due to propagation delays.
- Initial Block Download (IBD)
- The process of syncing a fresh node from the genesis block to the current tip. Takes 1-7 days for Bitcoin, longer for Ethereum, depending on hardware.
- Client diversity
- The existence of multiple independent software implementations of the same blockchain protocol. Strengthens decentralization by preventing any single client bug from compromising the network.
- Geth, Nethermind, Reth, Besu, Erigon
- The major Ethereum execution client implementations. Geth has historically dominated; Nethermind, Reth, and others provide diversity.
- Replace-by-Fee (RBF)
- A Bitcoin feature allowing users to broadcast a new version of an unconfirmed transaction with a higher fee, replacing the original. Useful for unsticking transactions during fee spikes.
- Gossip protocol
- The peer-to-peer mechanism by which transactions and blocks propagate through a blockchain network. Each node forwards new data to its peers, who forward to their peers, etc.
- Umbrel, Start9, MyNode, Citadel
- User-friendly Linux distributions for running Bitcoin and Lightning nodes at home, designed for non-technical users.
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Open lessonEducational only — not financial advice.