Here is an article on the way the MetaMask private sending a transaction the web3:
Obtaining your private metamask key for ethereum transactions
When together with Ethereum’s smart contractors use Web3 library, you probly want to sign to signs uses your private. Howver, not all users let their private keys readily available or access the mintamask. This is the wre Metamask isable.
Sign a transaction use the web3 and its private key
When creatamask account, you get two main types of Keys:
book Keys (or paper wallets)
and
Web3 keys (or methamask keys)
. To sign transactions Using your private metamask , follow these steps:
Step 1: Get your web3 ky
If you have a already set up a methamask web3 account, browse to the Metamask panel, wheree you can can you from view youb3 keys. You must see a list of Keys available in JSON format.
`Json
[[
{
"Address": "0x ...",
"Privatekey": "...",
"PUBLICKEY": "..."
"Name": "Your name"
},
...
]
In this example, we’ll call the first Key1key. Theddress (0x ...) and the private Key (...) arere what you will to signs.
Step 2: Subscribe to a transaction use web3
To sign a transaction use your web3 key, use the following code snippt:
`JavaScript
CONST Web3 = Requires (‘Web3’). standard;
// Replant ‘YourPravatekey’ with your royaal private key
Const Privatekey = “0x …”;
CONST TX = {
From: ‘0x …’, / / the contraction to the eddress to you want to send a send.
To: ‘0x …’, / / theddress of the recipient of the transaction.
Value: 100, //
Data: ‘Your transaction message.’ // a decreption of what the transaction is.
};
Web3.et.accounts.signtransaction (tx, privatekey, (error, signed) => {
if (error) console.error (error);
other {
Web3.et.SendSignedTransaction (SignedTX.Rawtransaction) .Then ((Result) => {
console.log (result);
}). Catch ((error) => {
console.error (error);
});
}
});
`
Example of case to:
Suppose you are triing to send a transaction from your metaamask. You credited an account on the Metamask panel and set up up a web3
`JavaScript
CONST Web3 = Requires (‘Web3’). standard;
// Replice ‘Yourprivatekey’ and ‘0x
Const Privatekey = “0x …”; // replace it without your royaal private key.
CONSTA CONTRACTADRESS = “0x …”; // Replac that it with the smart contraction to the eddress to what you want to send a transaction.
Web3.et.accounts.signtransaction ({
From: ‘0x …’, / / the contraction to the eddress to you want to send a send.
To: ContractedDRESS, / / / theddress of the recipient of the transaction.
Value: 100, //
Data: ‘Your transaction message.’ // a decreption of what the transaction is.
}, privatekey, (error, signed) => {
if (error) console.error (error);
other {
Web3.et.SendSignedTransaction (SigneDTX.Rawtransaction) .Ten ((Result) => {
console.log (result);
}). Catch ((error) => {
console.error (error);
});
}
});
`
In this example, we are signing a transaction uses to make your private Metamask portfolio and sending it to the contract. The signed transaction will be sent to Ethereum in exchange for ether specified in the the `Value&
I hope that help! Let you know if you have any any questions or need more assistance.