web3_clientVersion - Ethereum

Example code for the web3_clientVersion JSON RPC method. Сomplete guide on how to use web3_clientVersion JSON RPC in GetBlock Web3 documentation.

This method returns the current client version of the Ethereum execution node handling the request. Useful for detecting which client implementation (Geth, Nethermind, Besu, Reth, Erigon) is serving the endpoint and its version.

Parameters

This method takes no parameters.

Request

cURL

curl --location --request POST 'https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/' \
--header 'Content-Type: application/json' \
--data-raw '{
    "jsonrpc": "2.0",
    "method": "web3_clientVersion",
    "params": [],
    "id": "getblock.io"
}'

Axios

example.js

const axios = require('axios');

const response = await axios.post('https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/', {
    jsonrpc: '2.0',
    method: 'web3_clientVersion',
    params: [],
    id: 'getblock.io'
}, {
    headers: { 'Content-Type': 'application/json' }
});

console.log(response.data.result);

Request

example.py

import requests

response = requests.post(
    'https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/',
    headers={'Content-Type': 'application/json'},
    json={
        'jsonrpc': '2.0',
        'method': 'web3_clientVersion',
        'params': [],
        'id': 'getblock.io'
    }
)

print(response.json())

Rust

example.rs

use reqwest::Client;
use serde_json::{json, Value};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let client = Client::new();
    
    let response = client
        .post("https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/")
        .header("Content-Type", "application/json")
        .json(&json!({
            "jsonrpc": "2.0",
            "method": "web3_clientVersion",
            "params": [],
            "id": "getblock.io"
        }))
        .send()
        .await?
        .json::<Value>()
        .await?;
    
    println!("Result: {}", response["result"]);
    Ok(())
}

Response

{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": "Geth/v1.14.11-stable-f3c696fa/linux-amd64/go1.23.3"
}

Response Parameters

Parameter	Type	Description
jsonrpc	string	JSON-RPC protocol version ("2.0")
id	string	Request identifier matching the request
result	string	Client version identifier — format: Client/vX.Y.Z-metadata/OS-arch/lang-version

Use Cases

• Client Detection: Identify the underlying execution client to route client-specific extension calls (debug_*, trace_* availability varies by client)

• Compatibility Checks: Verify the node runs a version that supports a specific EIP or fork (e.g. Fusaka post-Dec 2025)

• Node Fingerprinting: Diagnose behavior differences across a multi-client fleet in incident response

• Client Diversity Monitoring: Track client-implementation distribution across endpoint fleets for decentralization audits

Error Handling

Error Code	Message	Description
-32603	Internal error	Node failed to return its client version string (transient upstream error)

Web3 Integration

Ethers.js

ethers-example.js

import { ethers } from 'ethers';

const provider = new ethers.JsonRpcProvider('https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/');

const clientVersion = await provider.send('web3_clientVersion', []);
console.log(clientVersion);

Viem

viem-example.js

import { createPublicClient, http } from 'viem';
import { mainnet } from 'viem/chains';

const client = createPublicClient({
    chain: mainnet,
    transport: http('https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/'),
});

const clientVersion = await client.request({ method: 'web3_clientVersion' });
console.log(clientVersion);