RPC method

eth_chainId on Telos EVM

Supported on SwiftNodes

Everything below was measured on 2026-10-13 by calling eth_chainId on Telos EVM through the same endpoint customers use, and is re-measured weekly.

What eth_chainId does

Returns the chain ID (EIP-155) as a hex string. Wallets and libraries check it before signing, and the signature commits to it, so a transaction signed for one chain cannot be replayed on another.

Telos EVM chain ID, as measured

net_version returns the same number as decimal text. Older tools read net_version; use eth_chainId, which is the value signatures commit to.

We sent Telos EVM a legacy transaction signed without a chain ID (pre-EIP-155). Its nodes refused it: "Revm error: Error sending transaction to Telos". Sign with chain ID 40; every mainstream library does this by default.

eth_chainId0x28 (40)
net_version40

Example request

curl -s https://rpc.swiftnodes.io/rpc/telos?key=YOUR_API_KEY \
  -X POST -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","id":1,"method":"eth_chainId","params":[]}'
// Check you are on Telos EVM before signing
import { createPublicClient, http } from "viem";

const client = createPublicClient({
  transport: http("https://rpc.swiftnodes.io/rpc/telos?key=YOUR_API_KEY"),
});

const id = await client.getChainId(); // 40
if (id !== 40) throw new Error(`wrong chain: ${id}`);

// Add Telos EVM to a browser wallet
await window.ethereum.request({
  method: "wallet_addEthereumChain",
  params: [{
    chainId: "0x28",
    chainName: "Telos EVM",
    nativeCurrency: { name: "TLOS", symbol: "TLOS", decimals: 18 },
    rpcUrls: ["https://rpc.swiftnodes.io/rpc/telos?key=YOUR_API_KEY"],
  }],
});

Other methods on Telos EVM

eth_chainId on other chains

Frequently asked questions

Does Telos EVM support eth_chainId?

Yes. eth_chainId answered on the SwiftNodes Telos EVM endpoint when our weekly probe called it through the customer path (2026-10-13).

What is the Telos EVM chain ID?

40 in decimal, 0x28 in hex, as returned by eth_chainId on 2026-10-13.

How do I add Telos EVM to MetaMask?

Call wallet_addEthereumChain with chainId 0x28, the native currency TLOS with 18 decimals, and your RPC URL; the example on this page has the full object.

Telos EVM endpoints, live block height and WebSocket status are on the Telos EVM RPC page.

One key covers every chain we serve, and SwiftNodes has a free tier.