What is a node in Blockchain and Crypto


20th October 2022


6 min


Antony Towle

Blockchain technology is changing how we validate transactions. From smart contracts to cryptocurrency networks‚ blockchain has given us a new and exciting method of sharing information. As more organisations‚ apps‚ and individuals embrace its possibilities‚ the need to know how the blockchain works grows.

That’s why it’s important to understand nodes. The most famous blockchain use cases include cryptocurrencies like Bitcoin and Ethereum‚ and other systems using a decentralised block of transactions. These – and indeed any other blockchains – run on nodes.

And‚ while you don’t have to fully understand the blockchain to use it‚ there’s no doubt that a little knowledge makes it clearer to trust and embrace the technology. We’ve seen it used in things like the bitcoin network‚ with many more uses on the horizon. Where could the blockchain take us next?

In this blog‚ we’ll look at:

  • What nodes are and how they contribute to blockchain networks
  • The different types of nodes and how they work in a full blockchain ecosystem
  • How the number of nodes in a blockchain help validate new transactions.

The role of nodes in Blockchain and crypto

Blockchain and cryptocurrency nodes are much like nodes in any other system. In computer science‚ a node is one device that plays a single role in contributing to a larger system. An example might be a server or storage device within a cloud computing platform. These nodes are in communication with each other‚ each carrying out the functions towards the system’s overall purpose.

In a blockchain‚ a node is typically a computer‚ laptop or cloud server that stores and exchanges blockchain data to help validate new transactions.

Why do they do this? Well‚ a blockchain is a distributed ledger that proves historical transaction records. There is no central power that holds these records. Instead‚ blockchains need a way to agree – they do this by keeping‚ essentially‚ a copy of the blockchain on each node‚ checking those records to come to a conclusion.

How do nodes work?

Each node holds a record of its blockchain’s transactions. For example‚ each full node on the Bitcoin blockchain holds a record of Bitcoin transactions. Then‚ when somebody tries to use Bitcoin in the future‚ checking against the blockchain can prove the owner has the Bitcoin they claim.

Once a new set of transactions (or block) happens‚ a record is sent to each node. They update their records accordingly. This peer-to-peer system means that it’s incredibly difficult to “fool” a blockchain – there are‚ in theory‚ many nodes‚ each storing identical proof of stake records.

Types of nodes

Not all nodes do the same job in a blockchain. Some nodes are designed to keep complete records for validating new blocks – but need to be constantly online and are resource-intensive. Other lightweight nodes might have much simpler jobs.

Why does a blockchain need multiple nodes? A basic answer is that the more nodes hold a record‚ the more difficult it would be to deceive the system. In theory‚ an entire blockchain could comprise a single node. But‚ if somebody were to change that node‚ there would be no way of knowing that its information is incorrect. Much like backups and disaster recovery in IT‚ more nodes on a blockchain means higher resiliency and trust.

Let’s look at the major types of blockchain nodes.

Full nodes

Full nodes in a blockchain act like a database. They store records of blockchain transactions‚ helping to verify what’s happened on that blockchain before.

A full node can be of two different types: pruned or archival.

Pruned full nodes

A pruned full node contains only part of the blockchain’s records. They exist because blockchains can grow to enormous sizes (in memory terms). For example‚ the Bitcoin blockchain grows by around 1MB per minute.

A pruned full node‚ instead‚ only stores part of those records‚ removing older transactions from its memory as new ones are written. This maintains the overall record‚ providing more nodes to the blockchain without employing huge storage space.

Archival full nodes

Archival full nodes‚ meanwhile‚ store a complete record of the entire blockchain. There are a few different kinds of archival full nodes:

  • Authority nodes: These nodes control aspects of a blockchain‚ granting new blockchain network nodes and settings various access controls and permissions.
  • Master nodes: These nodes are used to verify new block transactions and maintain the overall record of previous transactions.
  • Miner nodes: Mining nodes undertake the massive computational power needed for proof-of-work algorithms to verify a blockchain’s records.

Light nodes

Light nodes – as their name suggests – contain less information than full nodes. Typically‚ they’ll store block headers only‚ helping blockchains make faster checks or complete simple tasks.

Super nodes

In some blockchains‚ super nodes carry out additional work‚ such as implementing blockchain-wide rules or policies.

How to run a node

In theory‚ anybody can run a blockchain node – all they need is a copy of that blockchain’s transaction history. Then‚ by installing essential software and connecting to the blockchain‚ they can contribute to its successful ongoing work.

Who runs a node?

One of the key selling points of blockchain technology is precisely as described above: Anybody can contribute to a blockchain’s running. This creates its decentralised nature‚ removing the reliance on one central authority figure. Validation instead comes from checking the numerous copies of the ledger held on each node.

How to control a node

So‚ how could you control a node? By downloading any applicable software‚ you could become part of a functioning blockchain. For example‚ you might choose to run an Ethereum‚ Dash or Bitcoin node and contribute to the robustness of your favourite cryptocurrency – all you would need is the software‚ a strong internet connection‚ and enough resources to run your chosen type of node.

What are master nodes?

Master nodes‚ as mentioned earlier‚ provide a vital service in many blockchains. They do not add new transactions but verify and manage the blockchain’s ongoing processes. In some chains‚ they can also carry out particular services like protocols and rules management.

A master node needs a lot of memory and constant uptime. They’re essential to a blockchain’s functions‚ after all. As such‚ they’re usually hosted on cloud services with ample storage space and memory.

Who runs master nodes?

Many people would find it tricky to host a master node due to these huge resource demands. Master nodes also hold a degree of power over the blockchain‚ so barriers are put in place to prevent abuse of that power.

Many blockchains require a financial deposit to host a master node‚ for example. As they provide a vital service‚ master node hosts usually receive interest on that deposit or other crypto payments as a reward.


Nodes on a blockchain work together to provide an overall purpose. As a general rule‚ the more nodes there are‚ the more robust and reliable a blockchain is. By understanding how blockchains work‚ it’s possible to use their powers in novel ways – creating the systems‚ resources and mobile apps of the future.