🔌 Connect an existing account :

Once your provider is initialized, you can connect an existing account. You need 2 data :

• the address of the account
• the private key of this account

import { Account, ec, Provider } from "starknet";

Connect a predeployed account in Starknet-devnet :

When you launch starknet-devnet, 10 accounts are predeployed with 100 dummy ETH in each. Addresses and private keys are displayed on the console at initialization. These data will change at each launch ; to freeze them, launch with : starknet-devnet --seed 0. The result for account #0 :

Address: 0x7e00d496e324876bbc8531f2d9a82bf154d1a04a50218ee74cdd372f75a551a
Public key: 0x7e52885445756b313ea16849145363ccb73fb4ab0440dbac333cf9d13de82b9
Private key: 0xe3e70682c2094cac629f6fbed82c07cd

Then you can use this code :

// initialize provider
const provider = new Provider({ sequencer: { baseUrl:"<http://127.0.0.1:5050>"  } });
// initialize existing predeployed account 0 of Devnet
const privateKey = "0xe3e70682c2094cac629f6fbed82c07cd";
const starkKeyPair = ec.getKeyPair(privateKey);
const accountAddress = "0x7e00d496e324876bbc8531f2d9a82bf154d1a04a50218ee74cdd372f75a551a";

const account = new Account(provider, accountAddress, starkKeyPair);

Your account is now connected, and you can use it.

👛 Connect an existing account (in any network) :

The code is exactly the same, you have just :

• to connect to the appropriate network.
• to use the address of this account (public data).
• to use the private key of this account (very sensitive date : your code MUST not disclose it). For example, to connect an existing account to testnet, with a private key stored in .env non archived file :

import * as dotenv from "dotenv";
dotenv.config();

// intialize provider
const provider = new Provider({ sequencer: { baseUrl:"goerli-alpha"  } });
// initialize existing account
const privateKey = process.env.OZ_NEW_ACCOUNT_PRIVKEY;
const starkKeyPair = ec.getKeyPair(privateKey);
const accountAddress = "0x051158d244c7636dde39ec822873b29e6c9a758c6a9812d005b6287564908667";

const account = new Account(provider, accountAddress, starkKeyPair);