# eth\_chainId

The chain ID returned should always correspond to the information in the currently known head block. This ensures that the caller of this RPC method can always use the retrieved information to sign transactions built on top of the head.

If the currently known head block does not specify a chain ID, the client should treat any calls to `eth_chainId` as though the method was not supported, and returned a suitable error.

### **Parameters**

None.

### **Returns**

`QUANTITY` - integer of the current chain ID.

### **Example Request and Result for eth\_chainId**

Request

```
curl https://rpc-mainnet.u2u.xyz \
-X POST \
-H "Content-Type: application/json" \
-d '{"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":83}'
```

Result

```javascript
{
  "id": 83,
  "jsonrpc": "2.0",
  "result": "0x3d" // 61
}
```