How to check whether MetaMask is installed?

Question

How to check from client-side JavaScript whether MetaMask is installed?

score 8 · Answer 1 · answered Apr 03 '18 at 08:46

Not Metamask specifically, but the below checks if Web3 is being injected.

window.addEventListener('load', function() {

  // Check if Web3 has been injected by the browser (Mist/MetaMask).
  if (typeof web3 !== 'undefined') {
    // Use Mist/MetaMask's provider.
    web3js = new Web3(web3.currentProvider);
  } else {
    // Handle the case where the user doesn't have web3. Probably 
    // show them a message telling them to install Metamask in 
    // order to use the app.
  }

});

Anatoli Babenia · Accepted Answer · 2024-02-17T12:16:12.677

6

The recommended way is to use window.ethereum:

window.addEventListener('load', function() {
  if (window.ethereum) {
    console.log('Ethereum support is available')
    if (window.ethereum.isMetaMask) {
      console.log('MetaMask is active')
    } else {
      console.log('MetaMask is not available')
    }
  } else {
    console.log('Ethereum support is not found')
  }
})

edited Feb 17 '24 at 12:16

answered Jun 16 '18 at 05:20

Anatoli Babenia

321
2
14

1

github link is dead – alper May 09 '22 at 19:56
@alper fixed the link and updated code. Let me know if it works. – Anatoli Babenia Feb 07 '23 at 10:33
1

it works, thanks – alper Feb 08 '23 at 22:05

Luke Hutchison · Answer 3 · 2022-07-31T02:47:18.433

4

MetaMask's own onboarding library runs the test

window.ethereum && window.ethereum.isMetaMask

https://github.com/MetaMask/metamask-onboarding/blob/v1.0.1/src/index.ts#L169

Then create a Provider using new ethers.providers.Web3Provider(window.ethereum)

edited Jul 31 '22 at 02:47

answered Jul 31 '22 at 02:40

Luke Hutchison

420
3
11

score 3 · Answer 4 · answered Feb 28 '22 at 12:46

3

if (typeof window.ethereum !== 'undefined') {
  console.log('MetaMask is installed!');
}

Metamask documentation

answered Feb 28 '22 at 12:46

MantasFam

327
3
13

aakash4dev · Answer 5 · 2023-01-12T14:30:07.357

1

just 1 line: const isMetamask = ethereum.isMetaMask

it will return true or error.

edited Jan 12 '23 at 14:30

answered Dec 20 '22 at 10:31

aakash4dev

691
3
11

score 1 · Answer 6 · answered Jan 11 '23 at 01:38

Just to throw a different solution into the mix, here's a way to check on an interval in case you're up against loading issues. In this example, that interval is every second, it checks 15 times and then gives up.

((context) => {
  const checksBeforeStopping = 15
  let checksMade = 0
const interval = setInterval(() => {
    if (context?.ethereum?.isMetaMask) {
      console.log('MetaMask is installed')
      clearInterval(interval)
    } else console.log('Will check again in one second')
if (++checksMade === checksBeforeStopping) {
  clearInterval(interval)
  console.log('Giving up on checking for MetaMask')
}

}, 1000)
})(window)

score 1 · Answer 7 · answered Feb 16 '19 at 21:36

1

I found this answer on the Metamask github page https://metamask.github.io/metamask-docs/Advanced_Concepts/Provider_API#ethereum.on(eventname%2C-callback)

if (typeof window.ethereum !== 'undefined'
|| (typeof window.web3 !== 'undefined')) {

  // Web3 browser user detected. You can now use the provider.
  const provider = window['ethereum'] || window.web3.currentProvider
}

Then you call window.ethereum.enable() to request user permission

answered Feb 16 '19 at 21:36

Barrard

189
2
9

broken link but good answer – staminna Feb 23 '22 at 14:52
I think this is the correct link: https://docs.metamask.io/guide/getting-started.html#basic-considerations – MantasFam Mar 03 '22 at 09:46
1

window['ethereum'] is not a provider. You have to create a provider from this: new ethers.providers.Web3Provider(window.ethereum) – Luke Hutchison Jul 31 '22 at 02:46

How to check whether MetaMask is installed?

7 Answers7