eth_chainId

Overview

The 'eth_chainId' provided is always aligned with the data in the latest recognized head block. This guarantees that users of this RPC method can consistently utilize the fetched data to authenticate transactions based on the head.

If the recognized head block lacks a specified chain ID, the client will interpret calls to 'eth_chainId' as unsupported and will respond with an appropriate error.

For reliable chain identification, it's advised to prioritize 'eth_chainId' over 'net_version'.

Request

shell

curl --request POST \
     --url https://ethereum-mainnet-geth-archive.node.coinapi.io \
     --header 'accept: application/json' \
     --header 'content-type: application/json' \
     --header 'X-CoinAPI-Key: 73034021-THIS-IS-SAMPLE-KEY' \
     --data '
{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "eth_chainId"
}'

csharp

using RestSharp; {

var options = new RestClientOptions("https://ethereum-mainnet-geth-archive.node.coinapi.io");
var client = new RestClient(options);
var request = new RestRequest("");
request.AddHeader("accept", "application/json", "X-CoinAPI-Key: 73034021-THIS-IS-SAMPLE-KEY");
request.AddJsonBody("{\"id\":1,\"jsonrpc\":\"2.0\",\"method\":\"eth_chainId\"}", false);
var response = await client.PostAsync(request);

Console.WriteLine("{0}", response.Content); }

php

<?php

$curl = curl_init();

curl_setopt_array($curl, [
CURLOPT_URL => "https://ethereum-mainnet-geth-archive.node.coinapi.io",
CURLOPT_RETURNTRANSFER => true,
CURLOPT_ENCODING => "",
CURLOPT_MAXREDIRS => 10,
CURLOPT_TIMEOUT => 30,
CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
CURLOPT_CUSTOMREQUEST => "POST",
CURLOPT_POSTFIELDS => json_encode([
'id' => 1,
'jsonrpc' => '2.0',
'method' => 'eth_chainId'
]),
CURLOPT_HTTPHEADER => [
"accept: application/json",
"content-type: application/json",
"X-CoinAPI-Key": "73034021-THIS-IS-SAMPLE-KEY"
],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
echo "cURL Error #:" . $err;
} else {
echo $response;
}
?>

python

import requests

url = "https://ethereum-mainnet-geth-archive.node.coinapi.io"

payload = {
    "id": 1,
    "jsonrpc": "2.0",
    "method": "eth_chainId"
}
headers = {
    "accept": "application/json",
    "content-type": "application/json",
    "X-CoinAPI-Key" : "73034021-THIS-IS-SAMPLE-KEY"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

javascript

const options = {
  method: 'POST',
  headers: {accept: 'application/json', 'content-type': 'application/json', 'X-CoinAPI-Key' : '73034021-THIS-IS-SAMPLE-KEY'},
  body: JSON.stringify({id: 1, jsonrpc: '2.0', method: 'eth_chainId'})
};

fetch('https://ethereum-mainnet-geth-archive.node.coinapi.io', options)
  .then(response => response.json())
  .then(response => console.log(response))
  .catch(err => console.error(err));

go

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://ethereum-mainnet-geth-archive.node.coinapi.io"

	payload := strings.NewReader("{\"id\":1,\"jsonrpc\":\"2.0\",\"method\":\"eth_chainId\"}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("accept", "application/json")
	req.Header.Add("content-type", "application/json")
  req.Header.Add("X-CoinAPI-Key", "73034021-THIS-IS-SAMPLE-KEY")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

ruby

require 'uri'
require 'net/http'

url = URI("https://eth-mainnet.g.alchemy.com/v2/docs-demo")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["accept"] = 'application/json'
request["content-type"] = 'application/json'
request["X-CoinAPI-Key"] = '73034021-THIS-IS-SAMPLE-KEY'
request.body = "{\"id\":1,\"jsonrpc\":\"2.0\",\"method\":\"eth_chainId\"}"

response = http.request(request)
puts response.read_body

java

OkHttpClient client = new OkHttpClient();

MediaType mediaType = MediaType.parse("application/json");
RequestBody body = RequestBody.create(mediaType, "{\"id\":1,\"jsonrpc\":\"2.0\",\"method\":\"eth_chainId\"}");
Request request = new Request.Builder()
  .url("https://ethereum-mainnet-geth-archive.node.coinapi.io")
  .post(body)
  .addHeader("accept", "application/json")
  .addHeader("content-type", "application/json")
  .addHeader("X-CoinAPI-Key", "73034021-THIS-IS-SAMPLE-KEY")
  .build();

Response response = client.newCall(request).execute();

Response

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x1"
}

A hexadecimal of the current chain ID.

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