eth_simulateV1

​

Parameters:

1. simulationPayload - object - required

​

simulationPayload fields:

• blockStateCalls - array - required
  Array of block simulation objects. Each represents a simulated block.
• traceTransfers - boolean - optional
  If true, value transfers are included as logs. Defaults to false.
• validation - boolean - optional
  If true, applies validation checks such as nonce and balance. Defaults to false.

​

blockStateCalls object fields:

• calls - array
  List of transaction call objects to simulate
• stateOverrides - object - optional
  Override account state (balance, nonce, code, storage)
• blockOverrides - object - optional
  Override block-level fields (e.g. number, timestamp, baseFeePerGas)

​

call object fields:

• from - string - optional
  Sender address
• to - string - optional
  Recipient address. Omit it to simulate a contract creation
• maxFeePerGas - string - optional
  Max fee per gas (hex)
• value - string - optional
  Value sent (hex)
• data - string - optional
  Hex-encoded calldata

2. blockParameter - string - required

​

Returns:

​

Call result fields:

• status - string
  ”0x1” = success, “0x0” = failure
• gasUsed - string
  Gas used (hex)
• returnData - string
  Return data (hex)
• logs - array
  Emitted logs (includes transfers if enabled)
• error - string
  Error or revert reason (if failed)

// Result (block header fields other than number, hash, gasUsed and baseFeePerGas omitted)
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": [
    {
      "number": "0x3a636de",
      "hash": "0xfe0a79cf9b4bd07cb455f8ec20804a6e58e7fcb42da75f1afa59ed5f8cf9d34e",
      "gasUsed": "0x5343",
      "baseFeePerGas": "0x0",
      "calls": [
        {
          "returnData": "0x00000000000000000000000000000000000000000000008aabff43c24bb147b6",
          "logs": [],
          "gasUsed": "0x5343",
          "status": "0x1"
        }
      ]
    }
  ]
}

​

Example Request

curl https://mainnet.unichain.validationcloud.io/v1/<YOUR_API_KEY_HERE> \
    -X POST \
    -H "Content-Type: application/json" \
    -d '{"jsonrpc":"2.0","method":"eth_simulateV1","params":[{"blockStateCalls":[{"calls":[{"to":"0x4200000000000000000000000000000000000006","data":"0x18160ddd"}]}]},"latest"],"id":1}'