We're starting a new open network based on the Ethereum protocol. The question is how to allocate a network id for the new network. In Ethereum we have main net, four test networks, classic with test network etc.

Is there a list of network ids? If not, let's create one.


5 Answers 5


May be there is a list of network ids? If not, let's create one.

Good idea.

  • 0: Olympic, Ethereum public pre-release PoW testnet
  • 1: Frontier, Homestead, Metropolis, the Ethereum public PoW main network
  • 1: Classic, the (un)forked public Ethereum Classic PoW main network, chain ID 61
  • 2: Morden Classic, the public Ethereum Classic PoW testnet, now retired
  • 3: Ropsten, the public proof-of-work Ethereum testnet, now deprecated
  • 4: Rinkeby, the public Geth-only PoA testnet, now deprecated
  • 5: Goerli, the public cross-client PoA testnet
  • 6: Kotti Classic, the public cross-client PoA testnet for Classic
  • 7: Mordor Classic, the public cross-client PoW testnet for Classic
  • 10: Optimism, the Layer-2 EVM
  • 42: Kovan, the public Parity-only PoA testnet, now retired
  • 56: Binance, the public Binance mainnet
  • 69: Optimism's Kovan testnet
  • 77: Sokol, the public POA Network testnet
  • 99: POA Core, the public POA Network main network
  • 100: Gnosis Chain, the public xDAI/Gnosis main network
  • 1337: the private, local Geth development network
  • 42161: Arbitrum One, main network
  • 401697: Tobalaba, the public Energy Web Foundation testnet
  • 421611: Arbitrum test network
  • 11155111: Sepolia, the public proof-of-work Ethereum testnet
  • [Other]: Could indicate that you arr connected to a local development test network.

If you are looking for chain IDs not network IDs, check out: https://chainlist.org/


For any geth node to join a network there are 2 requirement one is to have the same genesis block and other is to have the same networkid. Once these requirements are satisfied, to join a network you have to know the enodeid of the nodes you want to connect to.

In case of open Ethereum networks like mainnet or testnet, you have a set of bootnodes hardcoded into your geth client where you can connect and discover other peers in the network. These bootnodes actually have a list of nodes that are connected to it in the last 24 hrs and they give out that list to you and then you can connect to those nodes. This is how you connect to other nodes in a Ethereum public network.

So if you want to create a new open network then create a genesis file, select some networkid, start some bootnodes and share these details about genesis file, networkid and list of bootnodes with the participants of network and then they will be able to join your network.

I don't think there is any constraint over which networkid to choose if we have done all the above steps correctly.


There is a website dedicated to tracking all EVM chains and their corresponding ids:


This is thanks to the Ethereum Lists initiative started by Ligi. Now the site is maintained by Yearn.Finance.

Chainlist.Org Screenshot

  • nice nice. would be nice to have it possibly sorted by chain id tho Commented May 25, 2020 at 13:13
  • Just opened an issue for this. Commented May 25, 2020 at 14:26
  • Note that network ID and chain ID are two different things and do not necessarily always have the same value!
    – q9f
    Commented May 18, 2022 at 12:45
ARBITRUM (mainnet) 42161 https://arb1.arbitrum.io/rpc https://arbiscan.io/|
ARBITRUM (testnet) 421611 https://rinkeby.arbitrum.io/rpc https://rinkeby-explorer.arbitrum.io/#/|
  • Hopefully others will build and update this answer. Would be too much to have new answers for each one :)
    – eth
    Commented Oct 1, 2021 at 5:27
  • As it’s currently written, your answer is unclear. Please edit to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers in the help center.
    – Community Bot
    Commented Oct 1, 2021 at 13:40

this is the api to get list of network ID's of blockchains registered. e.g. u can see at https://www.chain.link

from API (json): https://chainid.network/chains.json or https://api.llama.fi/chains, get the list of already present network id's, and choose the network id which is not already registered.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.