eth_getChainConfig - AVAX

Example code for the eth_getChainConfig JSON-RPC method. Complete guide on how to use eth_getChainConfig JSON-RPC in GetBlock Web3 documentation.

Returns the C-Chain runtime configuration — including all activated hard forks, fee config, and validator info. Avalanche-specific extension.

Parameters

• None

Request Example

cURL

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

JavaScript (Axios)

import axios from 'axios';

const data = JSON.stringify({
    "jsonrpc": "2.0",
    "method": "eth_getChainConfig",
    "params": [],
    "id": "getblock.io"
});

const config = {
    method: 'post',
    url: 'https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/ext/bc/C/rpc',
    headers: {
        'Content-Type': 'application/json'
    },
    data: data
};

axios(config)
    .then(response => console.log(JSON.stringify(response.data, null, 2)))
    .catch(error => console.log(error));

Python (Requests)

import requests
import json

url = "https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/ext/bc/C/rpc"

payload = json.dumps({
    "jsonrpc": "2.0",
    "method": "eth_getChainConfig",
    "params": [],
    "id": "getblock.io"
})

headers = {
    'Content-Type': 'application/json'
}

response = requests.post(url, headers=headers, data=payload)
print(response.text)

Rust (Reqwest)

use reqwest::Client;
use serde_json::json;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let client = Client::new();

    let payload = json!({
        "jsonrpc": "2.0",
        "method": "eth_getChainConfig",
        "params": [],
        "id": "getblock.io"
});

    let response = client
        .post("https://shared.eu-central-1.getblock.io/<ACCESS-TOKEN>/ext/bc/C/rpc")
        .header("Content-Type", "application/json")
        .json(&payload)
        .send()
        .await?;

    let result: serde_json::Value = response.json().await?;
    println!("{:#?}", result);

    Ok(())
}

Response Example

{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": {
        "chainId": 43114,
        "homesteadBlock": 0,
        "eip150Block": 0,
        "byzantiumBlock": 0,
        "constantinopleBlock": 0,
        "petersburgBlock": 0,
        "istanbulBlock": 0,
        "muirGlacierBlock": 0,
        "apricotPhase1BlockTimestamp": 1612230000,
        "apricotPhase2BlockTimestamp": 1620320400,
        "apricotPhase3BlockTimestamp": 1629839640,
        "apricotPhase4BlockTimestamp": 1633042200,
        "apricotPhase5BlockTimestamp": 1638203000,
        "banffBlockTimestamp": 1669144680,
        "cortinaBlockTimestamp": 1684339200,
        "durangoBlockTimestamp": 1712863200,
        "etnaTimestamp": 1727712000,
        "feeConfig": {
            "gasLimit": 15000000,
            "minBaseFee": 25000000000,
            "targetGas": 15000000,
            "baseFeeChangeDenominator": 36,
            "minBlockGasCost": 0,
            "maxBlockGasCost": 1000000,
            "targetBlockRate": 2,
            "blockGasCostStep": 200000
        }
    }
}

Response Parameters

Field	Type	Description
result.chainId	integer	Numeric chain ID (43114 mainnet, 43113 Fuji)
result.feeConfig	object	Dynamic fee configuration parameters
result.feeConfig.minBaseFee	integer	Minimum base fee in wei
result.feeConfig.gasLimit	integer	Block gas limit
result.feeConfig.targetBlockRate	integer	Target block production rate in seconds
result.*BlockTimestamp	integer	Activation timestamps for Avalanche upgrades (Apricot, Banff, Cortina, Durango, Etna)

Use Cases

• Detecting which protocol upgrades are active

• Adaptive fee oracles that respect the network's dynamic fee config

• Tooling that needs to know the block gas limit and target rate

Error Handling

Status Code	Error Message	Cause
404	Not Found	Missing or invalid <ACCESS-TOKEN>
-32602	Invalid params	Request parameters are missing or malformed
429	Too Many Requests	Rate limit exceeded for your plan

SDK Integration

Ethers.js

import { ethers } from 'ethers';

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

// Most methods are exposed directly on the provider.
// For raw access, use provider.send(method, params).
const result = await provider.send('eth_getChainConfig', []);
console.log(result);

Viem

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

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

const result = await client.request({ method: 'eth_getChainConfig', params: [] });
console.log(result);