# eth_chainId: parameters, returns and CU

> Original page: https://docs.blockvectra.com/en/api/json-rpc/methods/eth_chainId/

## Summary

Return the EIP-155 chain ID of the current network.

## Compute Units (CU) and Pricing

CU weight, price and per-chain availability are shown on the method page: https://docs.blockvectra.com/en/api/json-rpc/methods/eth_chainId/

## Parameters

This method takes no parameters.

## Returns

- **Type**: `QUANTITY`
- **Description**: Chain ID as a 0x-prefixed hexadecimal quantity (for example 0x1 on mainnet).

## Notes

The chain ID is part of EIP-155 transaction signing and stays constant for a network.

## Request Example

```bash
curl -X POST "https://dev-api.blockvectra.network/v1/robinhood_mainnet" \
  -H 'Content-Type: application/json' \
  -H 'x-api-key: <api_key>' \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_chainId",
    "params": [],
    "id": 1
  }'
```