hello

How to call the API from an app

const snapId = `npm:@hashgraph/hedera-wallet-snap`

const handleHelloAPI = async () => {
  await window.ethereum.request({
    method: 'wallet_invokeSnap',
    params: {
      snapId,
      request: {
        method: 'hello',
        params: {
          network: 'testnet',
          mirrorNodeUrl: 'https://testnet.mirrornode.hedera.com'
        }
      }
    }
  })
}

Note that you do not need to pass in "mirrorNodeUrl" but if you do, the snap will use that URL instead of the default public Hedera mirror nodes which may have rate limits associated with it.

What the API does

1. Retrieves the currently connected account the user has selected on Metamask. If it's the first time, a new snap account is created and the account info is saved in snap state.

2. Displays an alert dialog blox on Metamask with some content.

Some example responses:

For a hedera account id 0.0.3581604:

 {
    "currentAccount": {
        "metamaskEvmAddress": "0x0b3628d1b838993b5fceec8b2a26502e7a8e5241",
        "externalEvmAddress": "",
        "hederaAccountId": "0.0.3581604",
        "hederaEvmAddress": "0xca53f9c93d30e0b7212d67901e5a24fb090d542b",
        "publicKey": "0x0206022cea4c6dd6d2e7263b8802253971de922f5380661d97cba82dee66f57ad6",
        "balance": {
            "hbars": 5.67332072,
            "timestamp": "Wed, 13 Mar 2024 20:37:05 GMT",
            "tokens": {
                "0.0.3590430": {
                    "balance": 1,
                    "decimals": 1,
                    "tokenId": "0.0.3590430",
                    "name": "Token1",
                    "symbol": "KP1",
                    "tokenType": "FUNGIBLE_COMMON",
                    "supplyType": "INFINITE",
                    "totalSupply": "100",
                    "maxSupply": "0"
                }
            }
        },
        "network": "testnet",
        "mirrorNodeUrl": "https://testnet.mirrornode.hedera.com"
    }
}

Note that if you're connecting to the snap using MetaMask wallet(default option), metamaskEvmAddress will show your metamask wallet address and if you're connecting to the snap using an external account(importing using private key directly),externalEvmAddress will be empty.

Note that if you're connecting to the snap using MetaMask wallet(default option), the metamaskEvmAddress andhederaEvmAddresswill be different. This is because Hedera Wallet Snap creates a snap internal wallet as the snap has no direct access to the MetaMask wallet's private key.

Conversely, if you're connecting to the snap using an external account(importing using private key directly), externalEvmAddress andhederaEvmAddresswill be the same. This is because Hedera Wallet Snap has access to the private key of the external account so there is no need to create a snap internal wallet.

Live Demo on CodePen

Some things to keep in mind while interacting with the above demo

• If you're getting any errors with the live demo, make sure you go through the FAQs section to learn about what you may be missing. You need to install Metamask in your browser for the live demo to work

To ease the integration of Hedera Wallet Snap on an application, we have created a template web application that you can run locally and check out the code in its entirety to learn how you can integrate and interact with various APIs exposed by Hedera Wallet Snap. Check out the full source code at template application github repository.

You can also check out the API reference to learn how each API works.