eth_simulateV1

Simulates one or more transaction bundles against the current preconfirmed Flashblock state.

This method supports state overrides, block overrides, multi-block simulation, and optional ETH transfer tracing. This method will use 40 Compute Units.

---

Parameters:

params - array containing:

1. simulationPayload — object - required

Configuration object for the simulation.

simulationPayload fields:

• blockStateCalls — array - required Array of block simulation objects. Each represents a simulated block.

• traceTransfers — boolean - optional If true, ETH 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 Recipient address

• maxFeePerGas — string - optional Max fee per gas (hex)

• value — string - optional ETH value sent (hex)

• data — string - optional Hex-encoded calldata

1. blockParameter — string - required

Block number, hash, or tag.

Use "pending" to simulate against the latest Flashblock state.

Returns:

array of objects - simulated block results

Each object represents one simulated block.

Block result fields:

• number — string Block number (hex)

• hash — string Block hash

• gasUsed — string Total gas used (hex)

• baseFeePerGas — string Base fee (hex)

• calls — array Results of each simulated call

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)

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": [
    {
      "number": "0x29442bb",
      "hash": "0xcefc6e6e...",
      "gasUsed": "0x79ce",
      "calls": [
        {
          "returnData": "0x00000000000000000000000000000000000000000000000000000000011420f9",
          "logs": [],
          "gasUsed": "0x79ce",
          "status": "0x1"
        }
      ]
    }
  ]
}

Example Request

mainnet

curl https://mainnet.base.validationcloud.io/v1/<YOUR_API_KEY_HERE> \
  -X POST \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_simulateV1",
    "params": [
      {
        "blockStateCalls": [
          {
            "calls": [
              {
                "from": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
                "to": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
                "data": "0x70a08231000000000000000000000000d8dA6BF26964aF9D7eEd9e03E53415D37aA96045"
              }
            ]
          }
        ],
        "traceTransfers": true,
        "validation": false
      },
      "pending"
    ],
    "id": 1
  }'

testnet