curl https://site1.moralis-nodes.com/optimism/:apiKey \
  -X POST \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc": "2.0", "method": "eth_chainId", "params": [], "id": 1}'

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x1"
}