eth_simulateV1

Simulates one or more transaction bundles against the canonical chain state at the block you specify. Supports state overrides, multi-block simulation, and optional transfer tracing. The simulation does not broadcast transactions or change chain state.

Parameters

object

required

The simulation configuration.

Show Simulation Payload Fields

array

required

Array of block state call objects. Each object represents one simulated block.

Show Block State Call Fields

array

Array of transaction call objects to simulate within this block.

object

Per-address state overrides applied before simulation (e.g., balance, nonce, code, storage). Optional.

object

Block-level overrides (e.g., number, timestamp). Optional.

boolean

If true, ETH transfer events are included as logs in the result. Defaults to false.

boolean

If true, transaction validation (nonce, balance) is enforced. Defaults to false.

string

required

Block to simulate on top of: a block number in hex, or "latest", "pending", "safe", or "finalized". On Base, "pending" resolves to the latest canonical block, so "latest" and "pending" return the same state.

Returns

array

Array of simulated block results, one per entry in blockStateCalls. Each entry is a full block object with a calls field embedded alongside standard block fields.

Show Block Result Fields

string

Simulated block number (hex).

string

Simulated block hash.

string

Parent block hash.

string

Block timestamp (hex).

string

Gas limit (hex).

string

Total gas used by the simulated calls (hex).

string

Base fee per gas (hex).

string

Always "0x000...000" — simulation does not commit state to the trie.

array

Array of individual call results.

Show Call Result Fields

string

"0x1" for success, "0x0" for failure.

string

Gas used as a hexadecimal integer.

string

Hex-encoded return data.

array

Logs emitted (including ETH transfer logs if traceTransfers is true).

string

Revert reason if the call failed. Optional.

Example

curl https://sepolia.base.org \
  -X POST \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_simulateV1",
    "params": [
      {
        "blockStateCalls": [
          {
            "calls": [{"to": "0x...", "data": "0x..."}],
            "stateOverrides": {}
          }
        ],
        "traceTransfers": true,
        "validation": true
      },
      "latest"
    ],
    "id": 1
  }'

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": [
    {
      "baseFeePerGas": "0x0",
      "blobGasUsed": "0x39d0",
      "calls": [
        {
          "gasUsed": "0x5208",
          "logs": [],
          "returnData": "0x",
          "status": "0x1"
        }
      ],
      "difficulty": "0x0",
      "excessBlobGas": "0x0",
      "extraData": "0x01000003e80000000f00000000004c4b40",
      "gasLimit": "0x7270e00",
      "gasUsed": "0x5208",
      "hash": "0x2f2f692821995e39653f63164b2d5d0e0bba66c86c2a199fd3009c0b9906c7b0",
      "logsBloom": "0x000...000",
      "miner": "0x4200000000000000000000000000000000000011",
      "mixHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
      "nonce": "0x0000000000000000",
      "number": "0x2c31c49",
      "parentBeaconBlockRoot": "0x64e625f8bc74f78539f962aa09d522c63576ff6ad57170c668882d99e669ef52",
      "parentHash": "0x9653660afa4fca3976a21d42ebf849c337e9840993f050fee3affc673a573bf8",
      "receiptsRoot": "0xf78dfb743fbd92ade140711c8bbc542b5e307f0ab7984eff35d751969fe57efa",
      "requestsHash": "0xe3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
      "sha3Uncles": "0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347",
      "size": "0x2a6",
      "stateRoot": "0x0000000000000000000000000000000000000000000000000000000000000000",
      "timestamp": "0x6a10957f",
      "transactions": [
        "0xa401668a06b038c488c1abc013676dfe63fc645d182ece34d8b3f40f45689279"
      ],
      "transactionsRoot": "0x0b1328c457d7a8108ea9f2559142890491b680fdb691720b3d0c857c3d11002c",
      "uncles": [],
      "withdrawals": [],
      "withdrawalsRoot": "0x0000000000000000000000000000000000000000000000000000000000000000"
    }
  ]
}

Overview

CLIs

Base Chain API

Tokenized Stocks API

Base Earn API

Base Verify API

Migrated Documentation

Parameters

Returns

Example

​Parameters

​Returns

​Example

Parameters

Returns

Example