curl --request POST \
  --url https://api.mainnet.abs.xyz/zks_L1ChainId \
  --header 'Content-Type: application/json' \
  --data '
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "zks_L1ChainId",
  "params": []
}
'

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