Interacting With the Testnet

Once your local Emerald testnet is running, you can interact with it like any Ethereum network.

Using curl (JSON-RPC)

Get current block number:

curl -X POST http://127.0.0.1:8645 \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1}'

Get account balance:

curl -X POST http://127.0.0.1:8645 \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_getBalance","params":["0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266","latest"],"id":1}'

Send a transaction:

curl -X POST http://127.0.0.1:8645 \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc":"2.0",
    "method":"eth_sendTransaction",
    "params":[{
      "from":"0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266",
      "to":"0x70997970C51812dc3A010C7d01b50e0d17dc79C8",
      "value":"0x1000000000000000000",
      "gas":"0x5208"
    }],
    "id":1
  }'

Using cast (Foundry)

Prerequisite: Foundry

Get block number:

cast block-number --rpc-url http://127.0.0.1:8645

Check balance:

cast balance 0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266 --rpc-url http://127.0.0.1:8645

Send ETH:

cast send 0x70997970C51812dc3A010C7d01b50e0d17dc79C8 \
  --value 1ether \
  --private-key 0xac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80 \
  --rpc-url http://127.0.0.1:8645

Using Web3 Libraries

Configure your Web3 library to connect to http://127.0.0.1:8645:

ethers.js (JavaScript):

const { ethers } = require('ethers');

const provider = new ethers.JsonRpcProvider('http://127.0.0.1:8645');
const wallet = new ethers.Wallet('0xac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80', provider);

// Send transaction
const tx = await wallet.sendTransaction({
  to: '0x70997970C51812dc3A010C7d01b50e0d17dc79C8',
  value: ethers.parseEther('1.0')
});
await tx.wait();

web3.py (Python):

from web3 import Web3

w3 = Web3(Web3.HTTPProvider('http://127.0.0.1:8645'))
account = w3.eth.account.from_key('0xac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80')

# Send transaction
tx = {
    'to': '0x70997970C51812dc3A010C7d01b50e0d17dc79C8',
    'value': w3.to_wei(1, 'ether'),
    'gas': 21000,
    'gasPrice': w3.eth.gas_price,
    'nonce': w3.eth.get_transaction_count(account.address),
}
signed_tx = account.sign_transaction(tx)
tx_hash = w3.eth.send_raw_transaction(signed_tx.rawTransaction)

Using MetaMask

1. Open MetaMask and click on the network dropdown
2. Click “Add Network” → “Add a network manually”
3. Enter the following details:
   • Network Name: Emerald Local
   • RPC URL: http://127.0.0.1:8645
   • Chain ID: 12345 (or whatever you set in genesis)
   • Currency Symbol: ETH
4. Click “Save”
5. Import one of the test accounts using its private key

Warning

Only use test private keys with local networks. Never import test keys into wallets used for real funds.