Node (Node): The Invisible Pillar of Blockchain Network Operation

What actually happens behind the scenes when you buy and sell cryptocurrencies on an exchange? The answer is hidden in something called Node. If you think blockchain is just a bunch of data stored somewhere, you’re completely mistaken. In reality, thousands of Nodes are running simultaneously around the world, maintaining the normal operation of the entire cryptocurrency ecosystem.

Nodes are actually right around you

First, to understand, a Node is a computer connected to the blockchain network. It could be in an office, or in your home. Regardless of the form, these Nodes are doing one thing: participating in transaction validation and relaying.

When you initiate a transaction, it doesn’t go directly into the blockchain. Instead, it is first sent to various Nodes, which then check the validity of the transaction. If most Nodes agree that the transaction is valid, it will be packaged into a block and permanently recorded on the blockchain.

This is the core responsibility of a Node: acting as a “gatekeeper.” Without Nodes, there would be no transaction validation; without validation, there would be no blockchain. Projects like Bitcoin and Ethereum have survived to this day entirely thanks to those running Nodes.

How do Nodes work? Step-by-step breakdown

To understand the workflow of a Node, it can be divided into four key steps:

Step 1: Transaction broadcasting
After a user signs a transaction, the transaction information is sent to a group of Nodes. These Nodes, upon receiving the transaction, do not accept it immediately but continue to relay the transaction information to other Nodes. This process is like a relay race, with transaction data spreading across the network until all Nodes have received it.

Step 2: Transaction verification phase
Each Node maintains a “Mempool” — a “candidate transaction pool.” Upon receiving a transaction, the Node immediately checks it. This includes confirming whether the sender has sufficient balance, whether the signature is correct, whether the fee is reasonable, and so on.

Once the majority of Nodes agree that a transaction is valid, it moves from “pending review” to “ready for packaging.” If most Nodes find issues with the transaction, it is discarded outright. This self-protection mechanism is how blockchain maintains integrity.

Step 3: Packaging into a block
When a transaction is marked as “ready for packaging,” miners or validators can include it in a new block. Once the block is added to the chain, the transaction becomes immutable. Any attempt to modify this transaction would require approval from most Nodes — which usually means thousands of nodes agreeing, making it nearly impossible.

Step 4: Incentives and checks and balances
You might ask: why are these people willing to run Nodes? The answer lies in the incentive mechanisms.

In PoW (Proof of Work) systems like Bitcoin, miners need to solve complex mathematical puzzles to gain the right to package a block. Successful miners receive newly minted bitcoins as a reward. But this also acts as a defense — if miners try to cheat, their massive computational costs are wasted.

In PoS (Proof of Stake) systems like Ethereum, validators lock up a certain amount of tokens as a “deposit.” If they act honestly, they earn more rewards; if they cheat, their deposit is forfeited. This clever design uses economic incentives to ensure Node behavior aligns with network interests.

Why are Nodes so important? Three core reasons

1. Decentralized guardians
Imagine if all transactions required approval from a central authority—that’s no different from the current banking system. Thanks to thousands of independent Nodes operating, no single entity can control the entire network. Even if some Nodes fail or are attacked, others continue to operate. This is true decentralization.

2. Security assurance
To tamper with data on the blockchain, an attacker would need to control the majority of Nodes in the network. For large networks like Bitcoin and Ethereum, this would cost hundreds of millions of dollars. This mathematical security is made possible by the distributed and numerous Nodes.

3. Democratic participation
Anyone can run a Node. No special permission is needed, nor approval from an authority. This means ordinary users, developers, and businesses all have equal rights to participate in maintaining the blockchain network.

What types of Nodes are there?

Not all Nodes are the same. Based on their functions and roles, Nodes can be divided into four main types:

Full Nodes
These are the most “complete” Nodes. They store the entire blockchain history. For Bitcoin, this means about 400GB of data. Full Nodes are the backbone of the network; new nodes synchronize by downloading the entire blockchain history from a Full Node.

Light Nodes
If Full Nodes “know everything,” Light Nodes “know the essentials.” They do not store the entire blockchain, only the block headers. This allows Light Nodes to run on low-power devices like smartphones and tablets. They verify transactions using a technology called SPV (Simplified Payment Verification), without needing the full data.

Miner Nodes
In PoW systems, miner Nodes compete to package new blocks. They require significant computational power to solve mathematical puzzles. Successful miners earn newly created cryptocurrency and transaction fees as rewards.

Validator Nodes
In PoS systems, validator Nodes replace miners. They do not need computational power but lock up a certain amount of tokens as a “stake.” They are randomly selected to package blocks. Their tasks are to verify transactions and generate new blocks, in a more energy-efficient way.

Want to run a Node? Here’s how

If you’re interested in supporting a blockchain or want to participate more deeply, you can consider running your own Node. The steps are actually straightforward:

Prepare hardware
First, you need a sufficiently powerful computer. For a Full Node, at least 500GB of storage is required. A stable internet connection is also crucial — good bandwidth ensures your Node stays synchronized with others.

Download and install software
Each blockchain has its own Node software. For example, Bitcoin has Bitcoin Core, Ethereum has Geth, etc. Download the appropriate software and follow the instructions to install.

Start and keep it running
Once installed, launch the software. Your Node will begin synchronizing blockchain data. This process can take hours or days, depending on the size of the blockchain and your network speed. Once synchronized, your Node will participate in network validation.

Risks of running a Node

Of course, nothing is without risks. Some potential risks include:

Malware attacks
If your device is infected with malware, attackers could steal your private keys or other sensitive information. Keep your system updated, use firewalls, and scan regularly.

DDoS attacks
Although less common, attackers might attempt Distributed Denial of Service (DDoS) attacks to take your Node offline. Using firewall rules and limiting connections can mitigate this risk.

Sybil attacks
Attackers could create many fake Nodes to try to control a significant portion of the network. While difficult on large networks, small blockchains are more vulnerable.

Chain split risks
Running outdated Node software during network upgrades could cause your Node to become “isolated” on an old chain, leading to data inconsistency or failed transactions. Regular updates are key to avoiding this.

Final words

In a sense, Nodes are the physical carriers of the blockchain dream. Without Nodes, there is no decentralization; without decentralization, cryptocurrencies lose their core value.

For those wanting to deeply understand blockchain, understanding Nodes is essential. For those wishing to participate, running a Node is not only a contribution to the network but also a way to improve your skills. Whether you’re an investor, developer, or tech enthusiast, Nodes are worth your time to learn about.

Next time you hear someone mention Nodes, you’ll know it’s far more than just a technical term — it’s the fundamental backbone of the entire blockchain ecosystem.