How to detect if on mainnet or testnet?

Question

Is it possible to figure out whether the network is mainnet or testnet (Ropsten) from web3.js? Or through MetaMask?

Use ES6: await web3.eth.net.getNetworkType((err, network)=> {...}); — Russo, Oct 01 '18 at 14:12

Badr Bellaj · Accepted Answer · 2019-08-13T15:43:25.493

Prior to Web 1.0 you can use web3.version.getNetwork as following:

web3.version.getNetwork((err, netId) => {
  switch (netId) {
    case "1":
      console.log('This is mainnet')
      break
    case "2":
      console.log('This is the deprecated Morden test network.')
      break
    case "3":
      console.log('This is the ropsten test network.')
      break
    default:
      console.log('This is an unknown network.')
  }
})

WEB 1.0 :

Since web 1.0 we have web3.eth.net.getNetworkType which Guesses the network we are connected to.

web3.eth.net.getNetworkType()
.then(console.log);

It returns a string referring network's name :

"main" for main network
"morden" for the morden test network
"ropsten" for the ropsten test network
"private" for undetectable networks.

Use ES6: await web3.eth.net.getNetworkType((err, network)=> {...}); — Russo, Oct 01 '18 at 14:11

score 9 · Answer 2 · answered Jun 04 '17 at 16:09

9

web3.version.network or the async version web3.version.getNetwork() allow one to directly determine the network ID from web3.js.

Usage is as expected:

var network = web3.version.network

Network IDs can be found in this thread.

answered Jun 04 '17 at 16:09

Matthew Schmidt

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This might lead to exceptions stating that it is no good to access web3 methods synchronously. I had it this way and ran into issues in my rendering of react components, so i changed it to the accepted answer – David Fariña Mar 06 '18 at 17:56
1

web3.version.getNetwork() is asynchronous, for what it's worth. – Matthew Schmidt Mar 07 '18 at 23:21
youre right of course, but the only code fragment you actually formatted as code is the synchronous version which should be avoided, especially since there is a async variant. Didnt want to make your post down or anything, just wanted to give a helpful sidenote on that topic – David Fariña Mar 08 '18 at 11:25

score 8 · Answer 3 · answered Mar 12 '18 at 15:01

For web3 1.0.0 you should do:

web3.eth.net.getId().then(netId => {
  switch (netId) {
    case 1:
      console.log('This is mainnet')
      break
    case 2:
      console.log('This is the deprecated Morden test network.')
      break
    case 3:
      console.log('This is the ropsten test network.')
      break
    default:
      console.log('This is an unknown network.')
  }
})

szerte · Answer 4 · 2017-10-08T15:04:18.350

In addition to @Badr's answer, there are two more test networks, Rinkeby and Kovan:

switch (networkId) {
  case "1":
    networkName = "Main";
    break;
  case "2":
   networkName = "Morden";
   break;
  case "3":
    networkName = "Ropsten";
    break;
  case "4":
    networkName = "Rinkeby";
    break;
  case "42":
    networkName = "Kovan";
    break;
  default:
    networkName = "Unknown";
}

UPDATE: web3@1.0.0 has a web3.eth.net.getNetworkType([callback]) function to get a network name guess

score 0 · Answer 5 · answered Jun 04 '17 at 16:04

Is it possible to figure out whether the network is mainnet or testnet (Ropsten) from web3.js?

This has been asked before, and is answered here: Getting Go-Ethereum current network id

In addition to these suggestions, you could take a look a the net_version RPC call.

Or through MetaMask?

The main MetaMask pop-up shows the network you're connected to in the top left. It also functions as a drop-down, to allow you to select which network you want it to connect to.

How to detect if on mainnet or testnet?

5 Answers5

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