What is an Ethereum Node? The Complete Guide

Most of the blockchain’s use cases revolve around its core strength of enabling a peer-to-peer system. Bitcoin employs it to conduct financial transactions without a third party, and Ethereum uses it with programmable contracts where any two parties can enter and execute a contract using only code and no human oversight.

This peer-to-peer communication network is how Ethereum simultaneously ticks the boxes of decentralization, transparency, and security.

And the workhorses behind this are the Ethereum nodes — a set of powerful participants in the world of blockchain, maintaining and validating every transaction within the Ethereum network. As decentralized actors, nodes enhance network security and enable the execution of smart contracts.

At the time of writing, over 10,000 nodes are active on the Ethereum network.

But, what exactly are Ethereum nodes? And why are they so fundamental to the working of the Ethereum network?

In this blog, we will explain what Ethereum nodes are, how they work, the different types of Ethereum nodes, and how you can run a node.

What is an Ethereum node?

An Ethereum node is a computer that keeps a record of all the transactions made on Ethereum, broadcasting it to other peer nodes. Broadcasting information between nodes ensures all the nodes are up-to-date with the latest Ethereum state. This process is called ‘synchronization’.

Simply put, a node is any computer that connects with other computers to form and interact with a network, in this instance, the Ethereum network.

Nodes also participate in verifying the transactions and validating the blocks before the miners add the block to the blockchain.

For all these interactions to happen between nodes and the Ethereum network, nodes need to run a ‘client software’. Oftentimes, the terms ‘clients’ and ‘nodes’ are used interchangeably while talking about Ethereum because of how closely they function. But, here are the stark differences between clients and nodes.

Ethereum clients vs. nodes

The Ethereum client is software that enables nodes to speak the ‘language’ of Ethereum, thereby being able to read and interact with blockchain data. They are a computer’s access gateway to Ethereum.

On the other hand, an Ethereum node is a computer that interacts with other computers (nodes) to store, process, and execute transactions. But for nodes to be able to do these, they need to run an Ethereum client to interact with the network.

Moving forward, let’s look at the different types of nodes.

What are the different types of nodes? Full vs. light vs. archive nodes

We know that each node is capable of storing a copy of the distributed ledger i.e. the Ethereum transaction history, balance of accounts, and much more. However, depending on the type of nodes, the information being stored can differ, thereby making each type of node useful for specific applications.

There are 3 common types of nodes we can see on Ethereum:

Full nodes

A full Ethereum node stores the entire Ethereum blockchain’s data, from the genesis block to the most recent block. It stores all transaction history, smart contract code, and account balances. This allows full nodes to independently verify and validate the entire blockchain while also executing smart contract instructions, if any.

However, running an Ethereum full node takes around 1 TB worth of storage at the time of writing and needs more as the blockchain grows larger over time. This further demands more computational resources to process and validate transactions.

Light nodes

Light nodes work by only storing the header of the blocks which contain timestamps and the hash of the previous block. These nodes are apt for low-memory and low-end computational devices like smartphones. However, they are limited in functionalities.

Light nodes are mostly used to verify the validity of blockchain data. They are incapable of participating in block validation or executing smart contracts. Another drawback of light nodes is their reliance on other nodes for certain missing data which makes the output a more probabilistic one rather than a guaranteed one.

Archive nodes

An archive node stores the entire blockchain data of Ethereum like a full node. Additionally, it also stores every state change since the first-ever block on the network. Technically, archive nodes are not a node type but a mode to scrape the entire blockchain history. Full nodes work in archive mode to access any data before the recent 128 blocks.

Archive nodes are necessary for highly-specific activities like block explorers, wallet providers, on-chain analytics, and investigation.

As obvious as it gets, archive nodes are pretty expensive to maintain. The synchronization process of archive nodes can take up to months along with constant maintenance.

Let’s now dive into the working of Ethereum nodes. This will help you understand the role of nodes in an Ethereum-based interaction.

How do Ethereum nodes work?

Saying “nodes are the workhorses in a blockchain” sounds fancy but what does this actually mean? Let’s dive into the working relationship between blockchain and Ethereum nodes.

Simply put, blockchain is a way for several unrelated parties to agree or reach a consensus on the validity of a certain transaction or data. This is put into action by the nodes reaching a consensus on the final accurate record by ensuring the transactions are within the rules defined by the Ethereum network.

The nodes, which can be anywhere in the globe, use these rules, aka consensus algorithm, to agree on the next valid state of a blockchain. On Ethereum, at least 66% of the nodes must agree on a specific state of the network as true. If not, the nodes reject the block as invalid. They also reject transactions that defy the rules of the network.

For example: If A tries to send 10 ETH to B while only having 9 ETH in their wallet, nodes reject this transaction.

The above working of the Ethereum nodes come to life with these three key functions:

Communication

The connectivity of nodes with other nodes and their peer-to-peer communication is the lifeline of Ethereum. This takes place in the networking layer of Ethereum, which is a set of protocols or rules that nodes have to adhere to while communicating.

Nodes communicate in two ways:

1. Gossiping:

Gossipping is a one-to-many communication process in which nodes broadcast and exchange information with other nodes. Gossiping is necessary for nodes to reach a consensus.

2. Swapping:

Swapping is a one-to-one communication that includes requests and responses between specific nodes. For example, decentralized applications (dApps) use specific remote procedure call (RPC) nodes to interact with the Ethereum blockchain.

Synchronization

All the nodes syncing to be a single source of truth ensures the integrity of the Ethereum blockchain. Simply put, synchronization is the process by which nodes get the most up-to-date information about the blockchain data. Ethereum Wire Protocol is the protocol that enables nodes to exchange and sync their blockchain data.

Ethereum nodes can sync in three ways:

1. Full sync: Nodes replicate the entire blockchain data. It also downloads all the transactions on the blockchain from the Genesis block and verifies it by computing each block.

2. Fast sync: Nodes take a snapshot of the blockchain state from its peer nodes. However, nodes don’t process any transactions and trust their peers rather than verify the data.

3. Light sync: Nodes store only the current state of Ethereum data. And when required, nodes fetch their data from archive nodes.

By now, we know how nodes communicate and synchronize with each other. These two functions play a key role in upholding the security and integrity of the Ethereum blockchain while also assisting in its decentralization.

Block verification

Earlier when Ethereum employed a proof-of-work consensus mechanism, miner nodes were performing complex mathematical computations to create a block and adding them to the blockchain. Now, after the Merge, Ethereum uses the proof-of-stake consensus, where validators have replaced miners.

Based on their stake (locked-up ETH), Ethereum chooses validators to propose and add the new blocks. After their proposal, nodes verify the correctness of received blocks, check for any signs of manipulation or tampering, and ensure that the blocks comply with the consensus rules and protocol.

The roles of Ethereum nodes in block verification are:

• Verify the validity of the transaction request. If valid, add it to the mempool (a pool of transaction requests waiting to be executed).
• Re-execute the transactions to verify the accuracy of the validator.
• Reject the transaction if the transactions are invalid for reasons like exceeding gas limits, invalid addresses, or even insufficient funds.
• Pass the valid transactions to the validator to add the block.

Bonus: A portion of the validator’s stake is slashed as a penalty for faulty validation.

Learning how an Ethereum node works is essential to understand its importance in the network and exploring the opportunity of running a node.

And rightly so, let’s now see how you can run an Ethereum node.

The 5 Steps to Running an Ethereum node

Running an Ethereum node provides several key benefits:

• Conduct private and secure Ethereum transactions,
• Vote on Ethereum Improvement Proposals (EIPS),
• Strengthen the network by reducing centralized points of failure,
• Resist censorship and take full custody of private keys.

Now, here is a brief explanation of how to run an Ethereum node:

Decide on the prerequisites

There are plenty of choices for the type of node operator one wants to become. You will need to choose the client implementation of both execution and consensus clients.

Likewise, you can go with either an all-cloud node setup or bring in hardware. This step involves choosing an approach to how you want the node to run.

Meet cloud or hardware requirements

Ethereum nodes can now be run using cloud-based providers like Amazon Web Services (AWS) and Google Cloud Platform (GCP). In fact, more than 50% of Ethereum nodes are hosted on AWS.

On the hardware front, Ethereum nodes can run even on consumer-grade computers. However, there are minimum requirements to be met. There are also plug & play options where vendors sell preconfigured machines, making it a simple purchase, connect, and run process for the consumer.

Download & run client software

Pick and download suitable execution and consensus client software for your node. Vet this software by verifying the public keys found on client release pages.

After this, the execution client can be run on testnets to make sure it is working correctly before you deploy it on the mainnet. Similarly with the consensus client, establishing a RPC connection is a top priority before any further action.

Configure client software

All the configurations on both execution and consensus clients will be set to default. They can be further customized to tailor them for specific applications like running a validator node or monitoring, etc. This includes choosing a network, between mainnet or testnet, enabling a local RPC connection, and more.

Add validators and run the node

In the setup of an Ethereum node, adding validators is the final step. The most preferred way is to stake 32 ETH and run your own validator node. However, it is not viable for one and all.

Hence, there exist staking pool services like Lido and RocketPool, which have a decentralized pool of node operators where users can start staking with as little as $100 worth of ETH.

If running the node is one aspect, a more important one is to maintain it through regular monitoring and maintenance. This can be done by regular updation of clients, creating new client services, and running additional services like developer tooling, wallet infrastructure, etc.

For a deeper dive into the nuances of running an Ethereum node, hardware specifications, client software options, and more, read this comprehensive guide.

Ethereum nodes in dApps

From interpreting logic to providing data, decentralized applications (or dApps) rely on nodes for almost everything.

They also have specific nodes, in the form of RPC nodes, that play an integral role in helping the dApps operate seamlessly. They act as a communication bridge between dApps and the Ethereum blockchain.

Here is how RPC nodes actually work in dApps:

• Ethereum nodes are responsible for executing smart contracts. They interpret and process the code within smart contracts enabling their execution.
• By connecting to Ethereum nodes, dApps access real-time and historical data stored on the Ethereum blockchain which is essential for dApp users.
• Blockchain events can trigger specific actions within dApps, courtesy of smart contracts. Only by connecting to nodes, dApps can read these events and respond accordingly, enabling real-time updates and interactions.
• Ethereum nodes replace the traditional central servers, thereby providing a decentralized infrastructure for dApps to thrive on.

Ethereum Nodes: The Backbone of the Blockchain

In conclusion, an Ethereum node is a crucial part of the Ethereum blockchain, maintaining a copy of all transactions. It verifies each transaction, provides security through decentralization, and enables the functionality of smart contracts. Understanding these nodes helps us appreciate the robust and complex infrastructure that makes Ethereum a leading platform in the blockchain ecosystem.

We hope this blog post has helped you better understand what an Ethereum node is, how it works, and why it’s so important for the blockchain.

If you have any questions, join 40,000+ other builders in our Discord community — or reach out to the team directly for more info on how to get started with smart accounts.

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Frequently Asked Questions (FAQs)

1. What is the difference between Ethereum nodes and Ethereum clients?

Ethereum nodes are mere computers on Ethereum that record and validate transactions and participate in network consensus. Ethereum clients, on the other hand, are the software implementations that nodes use to interact with the Ethereum network.

In simple terms, nodes are the actual entities participating in the network, while clients are the software that enables nodes to communicate with and operate on the Ethereum blockchain.

2. Why should I run my own Ethereum node?

Running your own Ethereum node provides several benefits, both to you and the network. For you, it gives you the freedom to independently validate transactions, have direct access to blockchain data, enhance privacy and security, and participate in network governance. For the network, your node contributes to further decentralization and resilience.

3. Can I run an Ethereum node on a smartphone?

Yes, it is possible to run a light node on a smartphone due to its reduced storage and resource requirements. Light nodes are well-suited for mobile devices, allowing users to interact with the Ethereum network, send transactions, and access blockchain data using mobile applications. However, the functionalities of the node will be limited to verifying blockchain data.