A blockchain node is a computer that runs the blockchain software, maintains a copy of the ledger, and validates transactions.
What Nodes Do
| Function | Description |
|---|
| Validate transactions | Check signatures, balances, and rules |
| Store the ledger | Keep a copy of the entire blockchain |
| Propagate data | Broadcast transactions and blocks to other nodes |
| Reach consensus | Agree on the state of the network |
| Serve data | Provide blockchain data to wallets and dApps |
Types of Nodes
| Node Type | Full Copy? | Validates? | Consensus? |
|---|
| Full node | Yes | Yes | Yes |
| Light node | No (headers only) | Limited | No |
| Archive node | Yes (full history) | Yes | Yes |
| Pruned node | Yes (recent only) | Yes | Yes |
| Validator node | Yes | Yes | Yes (PoS) |
| Mining node | Yes | Yes | Yes (PoW) |
Full Node
| Resource | Requirement |
|---|
| Storage (Ethereum) | 1TB+ SSD |
| Storage (Bitcoin) | 600GB+ |
| RAM | 8-16GB |
| Bandwidth | 500GB+/month |
| Uptime | Ideally 24/7 |
Running a full node supports the network but requires hardware and bandwidth.
Light Node
| Feature | Description |
|---|
| What it stores | Block headers only |
| How it validates | Assumes full nodes are correct |
| Storage | MBs, not GBs |
| Best for | Mobile wallets, resource-constrained devices |
Archive Node
| Feature | Description |
|---|
| What it stores | Full history + all intermediate states |
| Storage | 10TB+ |
| Best for | Block explorers, analytics, dApp developers |
Validator Node (Proof of Stake)
| Requirement | Ethereum |
|---|
| Minimum stake | 32 ETH |
| Hardware | Moderate |
| Reward | ~3-5% APY |
| Penalty for downtime | Slashing (loss of ETH) |
How Nodes Communicate
| Protocol | Purpose |
|---|
| Gossip protocol | Broadcast transactions and blocks |
| Handshake | Peer discovery |
| Sync protocol | Download and verify the blockchain |
| DevP2P (Ethereum) | Node-to-node communication |
Who Runs Nodes
| Entity | Typical Node |
|---|
| Exchanges | Full nodes for transaction verification |
| Block explorers | Archive nodes |
| Staking providers | Validator nodes |
| Developers | Full nodes for testing |
| Individuals | Full or light nodes |
Why Run Your Own Node
| Advantage | Why |
|---|
| Privacy | Don’t rely on third-party providers |
| Trust | Verify transactions yourself |
| Support the network | Strengthen decentralisation |
| No rate limits | Unlimited API access |
| Learn | Understand how blockchain works |
Why Not Run a Node
| Disadvantage | Why |
|---|
| Cost | Hardware, bandwidth, electricity |
| Maintenance | Updates, monitoring, troubleshooting |
| Time | Setup and maintenance take hours |
| No direct profit | Validators earn rewards; full nodes don’t |
Bottom Line
Nodes are the backbone of any blockchain. Full nodes store the entire ledger, validate transactions, and propagate data. Light nodes store only headers. Validator nodes secure proof-of-stake networks. Running your own node gives you privacy, full trust, and supports decentralisation, but requires hardware and maintenance. Most users rely on third-party nodes through wallets and exchanges.
This content is for educational purposes only. Not financial advice. Do your own research before investing.