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Monad API method that returns the chain ID of the current network. The chain ID is used for transaction signing to prevent replay attacks across different networks.
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Parameters

  • none

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Response

  • result — the current chain ID as a hexadecimal string:
    • Monad Mainnet: 0x8f (143)
    • Monad Testnet: 0x279f (10143)

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eth_chainId code examples

const { ethers } = require("ethers");

const provider = new ethers.JsonRpcProvider("CHAINSTACK_NODE_URL");

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

getChainId();

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Use case

A practical use case for eth_chainId is verifying that your application is connected to the correct network before sending transactions, which is essential for preventing accidental transactions on the wrong network.