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POST
/
35848e183f3e3303c8cfeacbea831cab
eth_chainId
curl --request POST \
  --url https://bsc-mainnet.core.chainstack.com/35848e183f3e3303c8cfeacbea831cab \
  --header 'Content-Type: application/json' \
  --data '
{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "eth_chainId",
  "params": []
}
'
{
  "jsonrpc": "<string>",
  "id": 123,
  "result": "<string>"
}
BNB API method that returns the current chain ID. Chain ID is used to sign replay-protected transactions and verify whether a network is the desired one. It was introduced in EIP-155.
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​
Parameters

  • none

​
Response

  • quantity — EIP-155 Chain ID
Use the Chainstack EVM Knife to convert the Chain ID from Hexadecimal to Decimal.

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eth_chainId code examples

const { Web3 } = require("web3");
const NODE_URL = "CHAINSTACK_NODE_URL";
const web3 = new Web3(NODE_URL);

async function getChainId() {
  const chain = await web3.eth.getChainId();
  console.log(chain);
}

getChainId();

​
Use case

One possible use case for the eth_chainId method in Ethereum is to determine which chain a user is connected to when using a DApp with the MetaMask browser extension. This can be useful to provide a customized user experience based on the specific chain that the user is interacting with.

Body

application/json
​
id
integer
default:1
​
jsonrpc
string
default:2.0
​
method
string
default:eth_chainId
​
params
array

Response

200 - application/json

The network Chain ID

​
jsonrpc
string
​
id
integer
​
result
string
Last modified on October 19, 2025