Top-to-bottom map of how an Ethereum node is structured

 Top-to-bottom map of how an Ethereum node is structured

🔵 TOP LEVEL: The Node

A “node” = Execution Client (EL) + Consensus Client (CL) working together.

                    ┌─────────────────────────┐
                    │        Ethereum Node     │
                    │ (EL client + CL client)  │
                    └─────────────────────────┘

🔥 1. CONSENSUS CLIENT (CL)

Main job: Follow PoS consensus, manage validators, attestations, sync committees, fork-choice.

Examples: Prysm, Lighthouse, Teku, Nimbus, Lodestar

✔ Components inside CL

Consensus Client
│
├── Beacon Node
│     ├── p2p Networking (gossip, sync)
│     ├── Beacon Chain database (slots, epochs, states)
│     ├── Fork Choice (LMD-GHOST)
│     ├── State Transition (processing blocks)
│     ├── Sync Committee logic
│     └── REST API (for monitoring)
│
└── Validator Client
      ├── Proposer duties
      ├── Attester duties
      ├── Aggregator duties
      ├── Slashing Protection DB
      └── Signs duties using private keys

✔ CL connects to:

  • Peers through libp2p

  • Execution Client via the Engine API (over authenticated RPC with JWT)

🔥 2. EXECUTION CLIENT (EL)

Main job: Handle EVM, transactions, mempool, execution, state.

Examples: Geth, Nethermind, Erigon, Besu, Reth

✔ Components inside EL

Execution Client
│
├── JSON-RPC Server
│      ├── eth_* endpoints
│      ├── debug_* 
│      └── txpool_* 
│
├── Transaction Pool (Mempool)
│      ├── Accepts txs from RPC
│      ├── Validates signatures, nonces, gas
│      └── Shares txs via p2p
│
├── EVM Engine
│      ├── Executes transactions
│      ├── Runs smart contract bytecode
│      ├── Reads/writes state trie
│      └── Computes gas usage
│
├── State DB (LevelDB/RocksDB)
│      ├── State Trie (accounts + storage roots)
│      ├── Storage Tries
│      ├── Contract bytecode (codeHash → bytecode)
│      └── Chain history
│
└── P2P Network (devp2p)
       ├── tx propagation
       ├── block propagation
       └── chain syncing

✔ EL connects to:

  • Consensus Client via Engine API

  • External users/apps via RPC

  • Peers via devp2p

🔥 3. ENGINE API (CL ↔ EL BRIDGE)

This is the bridge between PoS consensus and execution.

CL <── Engine API (JWT auth) ──> EL

Used for:

  • newPayload (CL gives block payload to EL)

  • getPayload (EL gives proposed block to CL)

  • forkchoiceUpdated

  • validator duties

  • syncing

This connection makes sure:

  • CL decides which block is canonical

  • EL executes the block and updates the state

🔥 4. VALIDATOR CLIENT (VC)

A validator client connects to the consensus client (never to EL directly).

Validator Client
   │
   ├── Pays attention to CL
   ├── Signs duties (attest/propose)
   └── Uses slashing protection

🔥 5. DEVELOPERS & USERS (External)

They interact only with Execution Client RPC.

Wallets / Apps / Scripts / Dapps
         │
         ▼
     RPC Endpoints (EL)
         │
         ▼
      Execution Client

Examples of RPC methods:

  • eth_sendRawTransaction

  • eth_call

  • eth_getBalance

  • eth_getLogs

  • eth_getBlockByNumber

🌐 THE COMPLETE MAP (FULL DIAGRAM)

                                        ┌────────────────────────────┐
                                        │         USERS / DAPPS       │
                                        │   Wallets, Scripts, Bots    │
                                        └──────────────┬─────────────┘
                                                       │
                                               JSON-RPC (HTTP/Websocket)
                                                       │
                                                       ▼
                                     ┌─────────────────────────────────────┐
                                     │          EXECUTION CLIENT           │
                                     │    (Geth / Nethermind / Erigon)     │
                                     ├─────────────────────────────────────┤
                                     │                                     │
                                     │  • devp2p Network                   │
                                     │  • Tx Pool (mempool)                │
                                     │  • JSON-RPC Server                  │
                                     │  • EVM (executes code)              │
                                     │  • State DB (tries, code, storage)  │
                                     │                                     │
                                     └───────────────┬─────────────────────┘
                                             Engine API (JWT)
                                                     │
                                                     ▼
                          ┌────────────────────────────────────────────────────┐
                          │                   CONSENSUS CLIENT                 │
                          │    (Prysm / Lighthouse / Teku / Nimbus / Lodestar) │
                          ├────────────────────────────────────────────────────┤
                          │                                                    │
                          │  • libp2p Network                                  │
                          │  • Beacon Chain DB                                 │
                          │  • Fork Choice (LMD-GHOST)                         │
                          │  • State Transition                                │
                          │  • Sync Committees                                 │
                          │  • Block validation                                │
                          │                                                    │
                          └───────────────┬────────────────────────────────────┘
                                          │
                                 Validator API
                                          │
                                          ▼
                                ┌──────────────────────┐
                                │   VALIDATOR CLIENT   │
                                │  (signs duties only) │
                                └──────────────────────┘

🔥 SUMMARY (Perfect mental model)

  • Consensus Client ⇒ Decides which block is valid (attestations, PoS rules)

  • Execution Client ⇒ Executes what’s inside the block (EVM, state)

  • Engine API ⇒ Bridge between EL & CL

  • Validator Client ⇒ Signs duties only

  • RPC Server ⇒ Entry point for wallets/dApps

Comments

Post a Comment

Popular posts from this blog

Frontend-to-Blockchain Flow

Understanding the Frontend-to-Blockchain Flow: A Complete Guide As a Web3 developer, one of the most confusing aspects when starting out is understanding how your frontend actually communicates with the blockchain. Let me break down the entire flow from smart contracts to user interaction. The Complete Development Flow 1. Smart Contract Development & Deployment Your Starting Point: You have an application idea (decentralized, of course!) You write smart contracts with all your application's core logic Choose the right blockchain based on your requirements: Ethereum : Most secure, highest adoption Polygon : Low fees, fast transactions BSC (Binance Smart Chain) : Lower costs, high throughput Avalanche : Fast finality, customizable subnets Deployment Outputs: Contract Address Contract ABI (Application Binary Interface) The Frontend Integration Challenge Now you have a frontend and want users to interact with your deployed contracts. Here's where it gets interestin...
Read more

Arbitrum vs Optimism Rollups

Image
  Arbitrum vs Optimism Rollup Big picture first (same for both) Both Optimism and Arbitrum are: Optimistic rollups Assume transactions are correct by default Post: Compressed transaction data to Ethereum (for data availability) State roots to Ethereum Allow fraud proofs during a challenge window (~7 days) So security model = Ethereum L1 Now the real differences are in: Execution model Fraud proof design How user operations are processed internally How user operations (transactions) enter the system Common flow (both) User sends a transaction It goes to a Sequencer Sequencer: Orders transactions Executes them Produces a new L2 state Sequencer submits: Transaction data → Ethereum calldata State root → Ethereum contract Now differences begin. 2️⃣ Optimism: EVM-equivalent, simple execution 🧠 Core idea “Make L2 behave exactly like Ethereum, just cheaper.” How Optimism handles user operations Execution mo...
Read more