Running your own Ethereum node is a powerful way to engage directly with the blockchain—enhancing privacy, security, and decentralization. Since The Merge, Ethereum operates using two distinct layers: the Execution Layer (EL) and the Consensus Layer (CL). To fully participate in the network, both client types must run in tandem. This guide walks you through setting up and synchronizing an EL and CL client on a local machine, using real-world tools and best practices.
Understanding Nodes and Clients
“Run a Node” and “Run a Client” refer to the same action.
Ethereum is a decentralized network composed of nodes. Each node runs software known as a client, which implements Ethereum’s protocol rules—including how transactions, blocks, and smart contracts are processed via the Ethereum Virtual Machine (EVM). A fully functioning Ethereum node performs several key tasks:
- Downloads and verifies a complete copy of the blockchain
- Executes transactions and updates the global state
- Validates new blocks and transaction data
- Helps other peers sync by sharing data
As shown in official Ethereum documentation, a modern node consists of two separate components:
- Execution Layer Client (EL) – Handles transaction processing and state execution
- Consensus Layer Client (CL) – Manages proof-of-stake (PoS) consensus and block validation
This separation allows for modular development and improved network resilience.
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Execution Client vs. Consensus Client
What Is an Execution Client?
Also known as an Execution Engine or EL Client, this component manages user transactions, executes smart contracts via the EVM, and maintains the current state of the Ethereum database. It listens to the mempool (a pool of pending transactions), processes them, and produces updated states.
Popular execution clients include:
- Geth – Built with Go
- Nethermind – Developed in C#/.NET
These clients ensure that every transaction follows Ethereum’s ruleset before being considered valid.
What Is a Consensus Client?
Previously referred to as ETH2 clients, consensus clients (or Beacon Nodes) are responsible for implementing PoS consensus. They validate attestations, propose blocks, and enforce fork choice rules like LMD GHOST.
Examples include:
- Prysm – Written in Go
- Lighthouse – Built with Rust
By having multiple independently developed clients across different programming languages, Ethereum avoids centralization risks associated with single-codebase dominance. This diversity strengthens security and encourages broader developer participation.
How Do They Work Together?
The EL and CL communicate through the Engine API, a JSON-RPC interface defined in the execution-apis GitHub repository. This integration enables seamless coordination between transaction execution and block consensus.
Key points:
- The two clients authenticate each other using a JWT (JSON Web Token) secret
- Each CL client must be paired with exactly one EL client
- Multiple validators can connect to the same EL+CL pair
Validators—used by those who stake 32 ETH—are optional components that interact with the CL client to propose and vote on blocks. However, running a node does not require staking or running a validator.
The Impact of The Merge
Before The Merge in September 2022, Ethereum used Proof-of-Work (PoW), where miners executed transactions and reached consensus simultaneously. At that time, only one client handled both roles.
After The Merge:
- The original chain became the Execution Layer
- The Beacon Chain became the Consensus Layer, introducing PoS
- Now, both clients must operate together to maintain network integrity
This transition means all full nodes now require both an EL and CL client to stay synchronized with the latest blockchain state.
Who Should Run a Node?
Anyone can run an Ethereum node—no ETH ownership required. While validators earn rewards for securing the network, regular node operators gain critical benefits:
- Enhanced privacy: You don’t rely on third-party providers like Infura or Alchemy
- Greater security: Verify transactions independently
- Censorship resistance: Maintain control over which transactions you broadcast
- Network health: Support decentralization by increasing redundancy
Running a node doesn’t make you a validator—but every validator must run a node.
If you're building dApps, auditing smart contracts, or simply value sovereignty over your data, operating your own node is highly recommended.
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Node Types and Synchronization Modes
To join the network, clients must sync with the latest blockchain state. Different node types determine how much data is stored and verified:
- Full Nodes: Download all blocks and verify them using light proofs
- Archive Nodes: Store full historical state (requires terabytes of storage)
- Light Clients: Rely on trusted full nodes for data (low resource usage)
Synchronization modes vary between layers:
Execution Layer Syncing
- Full Sync: Downloads all headers, bodies, and state
- Snap Sync: Fast initial sync using snapshots of state data
- State Sync: Fetches latest state directly over the network
Consensus Layer Syncing
- Checkpoint Sync: Starts from recent finalized checkpoints (~hours instead of days)
- Historical Sync: Downloads all beacon chain history (slower but complete)
Choosing the right combination depends on your hardware and use case.
Step-by-Step: Running Your Own Clients
This tutorial uses:
- Nethermind as the Execution Client (rich documentation, .NET-based)
- Prysm as the Consensus Client (most widely adopted)
- Sepolia testnet for safe, no-cost experimentation
- macOS (M2 MacBook Pro), though steps are adaptable to Linux
Step 0: Set Up Directory Structure
Create a dedicated folder structure:
mkdir ethereum && cd ethereum
mkdir consensus executionResulting in:
ethereum/
├── consensus/
└── execution/Step 1: Install Consensus Layer Client (Prysm)
Navigate into the consensus directory:
cd consensus/prysm
curl https://raw.githubusercontent.com/prysmaticlabs/prysm/master/prysm.sh --output prysm.sh
chmod +x prysm.shGenerate authentication secret:
./prysm.sh beacon-chain generate-auth-secretYou’ll see output indicating version download. If you encounter:
gpg is not available...Set environment variable:
export PRYSM_ALLOW_UNVERIFIED_BINARIES=1Next, generate JWT token for EL–CL authentication:
openssl rand -hex 32 | tr -d "\n" > jwt.hexPlace jwt.hex in consensus/prysm/.
Step 2: Install Execution Layer Client (Nethermind)
On macOS with Homebrew:
brew tap nethermindeth/nethermind
brew install nethermindStep 3: Run the Execution Client
Start Nethermind with Sepolia configuration:
nethermind \
--config sepolia \
--JsonRpc.Enabled true \
--HealthChecks.Enabled true \
--JsonRpc.JwtSecretFile=../consensus/prysm/jwt.hex \
--Merge.TerminalTotalDifficulty 17000000000000000If port 8545 is in use:
lsof -i:8545
kill -9 <PID>Once running, it will wait for messages from the consensus layer.
Step 4: Run the Consensus Client (Beacon Node)
Download genesis.ssz from Sepolia’s merge-testnets repo into consensus/prysm.
Then start Prysm:
./prysm.sh beacon-chain \
--execution-endpoint=http://localhost:8545 \
--sepolia \
--jwt-secret=jwt.hex \
--genesis-state=genesis.sszYour beacon node will begin syncing with the network.
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Frequently Asked Questions (FAQ)
Q: Do I need ETH to run a node?
A: No. Running a node requires no ether. You only need ETH if you plan to become a validator by staking 32 ETH.
Q: Can I run both clients on the same machine?
A: Yes. Most developers run both EL and CL clients locally. Ensure sufficient RAM (16GB+) and SSD storage (500GB+ recommended).
Q: What’s the difference between a node and a validator?
A: A node verifies and relays data. A validator participates in consensus by proposing/voting on blocks—and must run both EL and CL clients.
Q: How long does syncing take?
A: EL snap sync: ~1–4 hours. CL checkpoint sync: ~30 minutes. Times vary based on internet speed and hardware.
Q: Can I use mainnet instead of Sepolia?
A: Yes. Replace --sepolia with --mainnet. Be aware that mainnet syncing requires more storage (~1TB eventually).
Q: Why are multiple client implementations important?
A: Diversity prevents single points of failure. If all nodes ran Geth, a critical bug could halt the network.
By running your own Ethereum node, you become an active participant in one of the world’s most resilient decentralized networks. With clear separation between execution and consensus layers, today’s Ethereum empowers users with unprecedented transparency and control.