> ## Documentation Index
> Fetch the complete documentation index at: https://docs.chainstack.com/llms.txt
> Use this file to discover all available pages before exploring further.

# eth_chainId | Arc

> Arc API method that returns the chain ID of the current network. Arc Mainnet is 5042 (0x13b2 in hexadecimal) and Arc Testnet is 5042002 (0x4cef52).

Arc API method that returns the chain ID of the current network. Arc Mainnet is `5042` (`0x13b2` in hexadecimal) and Arc Testnet is `5042002` (`0x4cef52`).

## Parameters

* `none`

## Response

* `result` — the chain ID encoded as hexadecimal (`0x13b2` for Arc Mainnet, `0x4cef52` for Arc Testnet)

## `eth_chainId` code examples

<CodeGroup>
  ```javascript ethers.js theme={"system"}
  const ethers = require('ethers');
  const NODE_URL = "CHAINSTACK_NODE_URL";
  const provider = new ethers.JsonRpcProvider(NODE_URL);

  const getChainId = async () => {
      const network = await provider.getNetwork();
      console.log(`Chain ID: ${network.chainId}`);
    };

  getChainId();
  ```

  ```python web3.py theme={"system"}
  from web3 import Web3

  node_url = "CHAINSTACK_NODE_URL"

  web3 = Web3(Web3.HTTPProvider(node_url))
  print(web3.eth.chain_id)
  ```

  ```bash cURL theme={"system"}
  curl -X POST "CHAINSTACK_NODE_URL" \
    -H "Content-Type: application/json" \
    -d '{"jsonrpc": "2.0", "method": "eth_chainId", "params": [], "id": 1}'
  ```
</CodeGroup>


## OpenAPI

````yaml openapi/arc_node_api/chain_info/eth_chainId.json POST /
openapi: 3.0.0
info:
  title: Chainstack Node API
  version: 1.0.0
  description: This is an API for interacting with a Chainstack node.
servers:
  - url: https://arc-testnet.core.chainstack.com/6caa7fd90475ac9214f7521dd460fa7c
security: []
paths:
  /:
    post:
      tags:
        - upload
      summary: eth_chainId
      operationId: eth_chainId
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                id:
                  type: integer
                  default: 1
                jsonrpc:
                  type: string
                  default: '2.0'
                method:
                  type: string
                  default: eth_chainId
                params:
                  type: array
                  default: []
      responses:
        '200':
          description: Returns the result of eth_chainId.
          content:
            application/json:
              schema:
                type: object
                properties:
                  jsonrpc:
                    type: string
                  id:
                    type: integer
                  result:
                    type: string
              example:
                jsonrpc: '2.0'
                id: 1
                result: '0x4cef52'

````