Simulate Transaction

This endpoint allows users to simulate the execution of a smart contract transaction on a specified blockchain network. The simulation provides detailed information about gas usage, execution trace, and potential outcomes without broadcasting the transaction to the network. This is useful for testing and validation purposes.

NOTE: Endpoint is under alpha preview and as such expect errors. Please do report any error over our official Discord channel.

Request

Authorization

Provide your bearer token in the

Authorization

header when making requests to protected resources.

Example:

Authorization: Bearer ********************

Path Params

networkId

integer <int64>

required

Network ID specifies the blockchain network (e.g., 1 for Ethereum Mainnet).

Default:

Example:

Query Params

sender

string

optional

Address from which the transaction is sent.

<= 42 characters

Example:

0xE5A173Cc9Bc3333ee8e89635764b9AB92D1da6ED

recipient

string

optional

Address to which the transaction is sent.

<= 42 characters

Example:

0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2

data

string

optional

Optional data payload for the transaction.

Example:

0xd0e30db0

gasLimit

integer <int64>

optional

Gas limit for the transaction.

Example:

600000

value

string

optional

Value of the transaction in Wei.

Example:

1000

blockNumber

integer <int64>

optional

Optional block number to simulate the transaction at (latest if not specified).

formatTrace

boolean

optional

Optional flag to format the trace.

Example:

true

Responses

🟢200OK

application/json

Body

$schema

string <uri>

read-onlyoptional

A URL to the JSON Schema for this object.

Example:

https://api.unpack.dev/schemas/SimulatedTransaction.json

blockNumber

integer <int64>

required

Block number at which the simulation was run.

bytes

string

optional

Bytecode result of the simulation.

completedStates

array[string]

optional

createdAt

string <date-time>

optional

Timestamp of the simulation.

decodedPayload

object (SimulatedTransactionDecoder)

required

Detailed decoding of the transaction input including function that was used

function

object (PartialFunction)

required

inputs

object

required

signature

string

required

exitReason

string

optional

Reason for exiting the simulation.

failedStates

array[string]

optional

formattedTrace

string

optional

Formatted trace of the simulation.

gasUsed

integer <int64>

required

Amount of gas used in the simulation.

logs

array[object (Log) {13}]

optional

Logs generated during the simulation.

abi

string

required

ABI

address

object (NamedAddr)

required

Log address

anonymous

boolean

required

Anonymous status

ast

object (EventDefinition)

required

AST event definition

data

object

required

Decoded log data

decodedTopics

array[object (Topic) {2}]

required

Decoded log topics

eventSignature

string

required

Event signature

name

string

required

Log name

rawData

string

required

Raw log data

removed

boolean

required

Removed status

signature

string

required

Log signature

topics

array[string]

required

Log topics

type

string

required

Log event type

networkId

integer <int64>

required

Network ID of the simulation.

partial

boolean

optional

Indicates if the simulation is partial or not.

processed

boolean

optional

Indicates if the simulation was successful.

recipient

object (NamedAddr)

required

Detailed address information to which the call was made.

sender

object (NamedAddr)

required

Detailed address information from which the call was made.

simulationId

string

required

ID of the simulation.

success

boolean

required

Indicates if the simulation was successful.

trace

array[object (SimulatedCallTrace) {4}]

required

Call trace of the simulation.

callType

string

required

Type of the call.

from

string

required

Address from which the call was made.

string

required

Address to which the call was made.

value

string

required

Value transferred in the call.

Example

{
  "$schema": "https://api.unpack.dev/schemas/SimulatedTransaction.json",
  "blockNumber": 0,
  "bytes": "string",
  "completedStates": [
    "string"
  ],
  "createdAt": "2019-08-24T14:15:22Z",
  "decodedPayload": {
    "function": {
      "$schema": "https://api.unpack.dev/schemas/PartialFunction.json",
      "abi": "string",
      "contractAddress": "string",
      "createdAt": "2019-08-24T14:15:22Z",
      "id": "string",
      "implemented": true,
      "mutability": "string",
      "name": "string",
      "parameters": [
        {
          "constant": true,
          "id": 0,
          "indexed": true,
          "name": "string",
          "nameLocation": {
            "column": 0,
            "end": 0,
            "length": 0,
            "line": 0,
            "parentIndex": 0,
            "start": 0
          },
          "nodeType": 0,
          "scope": 0,
          "src": {
            "column": 0,
            "end": 0,
            "length": 0,
            "line": 0,
            "parentIndex": 0,
            "start": 0
          },
          "stateMutability": 0,
          "stateVariable": true,
          "storageLocation": 0,
          "typeDescription": {
            "typeIdentifier": "string",
            "typeString": "string"
          },
          "typeName": {
            "expression": null,
            "id": 0,
            "keyNameLocation": {
              "column": 0,
              "end": 0,
              "length": 0,
              "line": 0,
              "parentIndex": 0,
              "start": 0
            },
            "keyType": {},
            "name": "string",
            "nodeType": 0,
            "pathNode": {
              "id": 0,
              "name": "string",
              "nameLocation": {
                "column": 0,
                "end": 0,
                "length": 0,
                "line": 0,
                "parentIndex": 0,
                "start": 0
              },
              "nodeType": 0,
              "referencedDeclaration": 0,
              "src": {
                "column": 0,
                "end": 0,
                "length": 0,
                "line": 0,
                "parentIndex": 0,
                "start": 0
              },
              "typeDescription": {
                "typeIdentifier": "string",
                "typeString": "string"
              }
            },
            "referencedDeclaration": 0,
            "src": {
              "column": 0,
              "end": 0,
              "length": 0,
              "line": 0,
              "parentIndex": 0,
              "start": 0
            },
            "stateMutability": 0,
            "typeDescription": {
              "typeIdentifier": "string",
              "typeString": "string"
            },
            "valueNameLocation": {
              "column": 0,
              "end": 0,
              "length": 0,
              "line": 0,
              "parentIndex": 0,
              "start": 0
            },
            "valueType": {}
          },
          "visibility": 0
        }
      ],
      "returnParameters": [
        {
          "constant": true,
          "id": 0,
          "indexed": true,
          "name": "string",
          "nameLocation": {
            "column": 0,
            "end": 0,
            "length": 0,
            "line": 0,
            "parentIndex": 0,
            "start": 0
          },
          "nodeType": 0,
          "scope": 0,
          "src": {
            "column": 0,
            "end": 0,
            "length": 0,
            "line": 0,
            "parentIndex": 0,
            "start": 0
          },
          "stateMutability": 0,
          "stateVariable": true,
          "storageLocation": 0,
          "typeDescription": {
            "typeIdentifier": "string",
            "typeString": "string"
          },
          "typeName": {
            "expression": null,
            "id": 0,
            "keyNameLocation": {
              "column": 0,
              "end": 0,
              "length": 0,
              "line": 0,
              "parentIndex": 0,
              "start": 0
            },
            "keyType": {},
            "name": "string",
            "nodeType": 0,
            "pathNode": {
              "id": 0,
              "name": "string",
              "nameLocation": {
                "column": 0,
                "end": 0,
                "length": 0,
                "line": 0,
                "parentIndex": 0,
                "start": 0
              },
              "nodeType": 0,
              "referencedDeclaration": 0,
              "src": {
                "column": 0,
                "end": 0,
                "length": 0,
                "line": 0,
                "parentIndex": 0,
                "start": 0
              },
              "typeDescription": {
                "typeIdentifier": "string",
                "typeString": "string"
              }
            },
            "referencedDeclaration": 0,
            "src": {
              "column": 0,
              "end": 0,
              "length": 0,
              "line": 0,
              "parentIndex": 0,
              "start": 0
            },
            "stateMutability": 0,
            "typeDescription": {
              "typeIdentifier": "string",
              "typeString": "string"
            },
            "valueNameLocation": {
              "column": 0,
              "end": 0,
              "length": 0,
              "line": 0,
              "parentIndex": 0,
              "start": 0
            },
            "valueType": {}
          },
          "visibility": 0
        }
      ],
      "signature": "string",
      "signatureDefinition": "string",
      "updatedAt": "2019-08-24T14:15:22Z",
      "virtual": true,
      "visibility": "string"
    },
    "inputs": {
      "property1": null,
      "property2": null
    },
    "signature": "string"
  },
  "exitReason": "string",
  "failedStates": [
    "string"
  ],
  "formattedTrace": "string",
  "gasUsed": 0,
  "logs": [
    {
      "abi": "string",
      "address": {
        "addr": "string",
        "ens": "string",
        "name": "string",
        "tags": [
          "string"
        ],
        "type": "string"
      },
      "anonymous": true,
      "ast": {
        "anonymous": true,
        "id": 0,
        "name": "string",
        "nodeType": 0,
        "parameters": {
          "id": 0,
          "nodeType": 0,
          "parameterTypes": [
            {
              "typeIdentifier": "string",
              "typeString": "string"
            }
          ],
          "parameters": [
            {
              "constant": true,
              "id": 0,
              "indexed": true,
              "name": "string",
              "nameLocation": {
                "column": 0,
                "end": 0,
                "length": 0,
                "line": 0,
                "parentIndex": 0,
                "start": 0
              },
              "nodeType": 0,
              "scope": 0,
              "src": {
                "column": 0,
                "end": 0,
                "length": 0,
                "line": 0,
                "parentIndex": 0,
                "start": 0
              },
              "stateMutability": 0,
              "stateVariable": true,
              "storageLocation": 0,
              "typeDescription": {
                "typeIdentifier": "string",
                "typeString": "string"
              },
              "typeName": {
                "expression": null,
                "id": 0,
                "keyNameLocation": {
                  "column": 0,
                  "end": 0,
                  "length": 0,
                  "line": 0,
                  "parentIndex": 0,
                  "start": 0
                },
                "keyType": {},
                "name": "string",
                "nodeType": 0,
                "pathNode": {
                  "id": 0,
                  "name": "string",
                  "nameLocation": {
                    "column": 0,
                    "end": 0,
                    "length": 0,
                    "line": 0,
                    "parentIndex": 0,
                    "start": 0
                  },
                  "nodeType": 0,
                  "referencedDeclaration": 0,
                  "src": {
                    "column": 0,
                    "end": 0,
                    "length": 0,
                    "line": 0,
                    "parentIndex": 0,
                    "start": 0
                  },
                  "typeDescription": {
                    "typeIdentifier": "string",
                    "typeString": "string"
                  }
                },
                "referencedDeclaration": 0,
                "src": {
                  "column": 0,
                  "end": 0,
                  "length": 0,
                  "line": 0,
                  "parentIndex": 0,
                  "start": 0
                },
                "stateMutability": 0,
                "typeDescription": {
                  "typeIdentifier": "string",
                  "typeString": "string"
                },
                "valueNameLocation": {
                  "column": 0,
                  "end": 0,
                  "length": 0,
                  "line": 0,
                  "parentIndex": 0,
                  "start": 0
                },
                "valueType": {}
              },
              "visibility": 0
            }
          ],
          "src": {
            "column": 0,
            "end": 0,
            "length": 0,
            "line": 0,
            "parentIndex": 0,
            "start": 0
          }
        },
        "src": {
          "column": 0,
          "end": 0,
          "length": 0,
          "line": 0,
          "parentIndex": 0,
          "start": 0
        },
        "typeDescription": {
          "typeIdentifier": "string",
          "typeString": "string"
        }
      },
      "data": {
        "property1": null,
        "property2": null
      },
      "decodedTopics": [
        {
          "name": "string",
          "value": null
        }
      ],
      "eventSignature": "string",
      "name": "string",
      "rawData": "string",
      "removed": true,
      "signature": "string",
      "topics": [
        "string"
      ],
      "type": "string"
    }
  ],
  "networkId": 0,
  "partial": true,
  "processed": true,
  "recipient": {
    "addr": "string",
    "ens": "string",
    "name": "string",
    "tags": [
      "string"
    ],
    "type": "string"
  },
  "sender": {
    "addr": "string",
    "ens": "string",
    "name": "string",
    "tags": [
      "string"
    ],
    "type": "string"
  },
  "simulationId": "string",
  "success": true,
  "trace": [
    {
      "callType": "string",
      "from": "string",
      "to": "string",
      "value": "string"
    }
  ]
}

🔴500Error

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