# Invoke Script Transaction

Invoke Script transaction invokes the callable function of the dApp. Learn more about dApp and script invocation

In addition to the dApp address, callable function name, and arguments, the Invoke Script transaction can contain up to two payments to dApp (one payment before activation of feature #15 “Ride V4, VRF, Protobuf, Failed transactions”).

# Fee

The sender can specify a transaction fee nominated in a sponsored asset instead of WAVES, see the Sponsored Fee article.

# Versions 2 and 1

The minimum fee in WAVES for an Invoke Script transaction is calculated as follows:

Fee = 0.005 + S + 0.004 × P + 0.004 × A + 1 × I

If the transaction sender is a dApp or smart account, then S = 0.004, otherwise S = 0.
The Invoke Script transaction can contain payments. P is the number of payments in smart assets.
The Invoke Script transaction can result in the token transfer, reissue or burning. A is the number of smart assets among these actions.
The Invoke Script transaction can result in the token issue. I is the number of issued assets that are not NFT.

See also the example in the Transaction Fee article.

# Version 3

Version 3 of the Invoke Script transaction is added in node version 1.3.0 and enabled with feature #16 “Ride V5, dApp-to-dApp invocations, Continuations”. Versions 1.3.x are now available for Stagenet only.

Fee = (0.005 + E) × ⌈С / 4000⌉ × + S + 0.004 × P + 0.004 × A + 1 × I + 0,004 × N,

where:

E is the extra fee specified in the extraFeePerStep field,

С is the complexity of the callable function. С/4000 rounded up to the nearest integer is the number of stages in the computation sequence. For details see the Continued Computations article.

N is the total number of nested invocations via Invoke function. For details see the dApp-to-dApp Invocation article.

Continued computations and dApp-to-dApp invocation are mutually exclusive, that is, they cannot be initiated by the same transaction.

# JSON Representation

{
  "type": 16,
  "id": "DN9Ny8mph4tLjn58e9CqhckPymH9zwPqBSZtcv2bBi3u",
  "sender": "3Mw48B85LvkBUhhDDmUvLhF9koAzfsPekDb",
  "senderPublicKey": "BvJEWY79uQEFetuyiZAF5U4yjPioMj9J6ZrF9uTNfe3E",
  "fee": 500000,
  "feeAssetId": null,
  "timestamp": 1601652119485,
  "proofs": [
    "2536V2349X3cuVEK1rSxQf3HneJwLimjCmCfoG1QyMLLq1CNp6dpPKUG3Lb4pu76XqLe3nWyo3HAEwGoALgBhxkF"
  ],
  "version": 2,
  "chainId": 84,
  "dApp": "3N28o4ZDhPK77QFFKoKBnN3uNeoaNSNXzXm",
  "payment": [],
  "call": {
    "function": "foo",
    "args": [
      {
        "type": "list",
        "value": [
          {
            "type": "string",
            "value": "alpha"
          },
          {
            "type": "string",
            "value": "beta"
          },
          {
            "type": "string",
            "value": "gamma"
          }
        ]
      }
    ]
  },
  "height": 1203100,
  "applicationStatus": "succeeded",
  "stateChanges": {
    "data": [
      {
        "key": "3Mw48B85LvkBUhhDDmUvLhF9koAzfsPekDb",
        "type": "string",
        "value": "alphabetagamma"
      }
    ],
    "transfers": [],
    "issues": [],
    "reissues": [],
    "burns": [],
    "sponsorFees": []
  }
}

Field	Description
call.function	Callable function name. Up to 255 bytes (1 character can take up to 4 bytes)
call.args.type	Argument type: - binary - boolean - integer - string - list (lists are available after activation of feature #15)
call.args.value	Argument value. - integer: from -9,223,372,036,854,775,808 to 9,223,372,036,854,755,807 inclusive. - string or binary: up to 32,767 bytes. Binary value should be base64 encoded. - list: up to 1000 elements
dApp	dApp address base58 encoded or dApp alias with `alias:<chain_id>:` prefix, for example `alias:T:merry` (see Chain ID)
payment.amount	Amount of token in payment: an integer value specified in atomic units
payment.assetId	ID of token in payment, base58 encoded. `null` means that the payment is in WAVES
stateChanges	Script actions performed by the callable function. In transaction version 3 the structure can also include dApp-to-dApp invocation result
extraFeePerStep	Extra fee for each stage of computations, see the Continued Computations article. The extra fee is specified in the same token as the transaction fee, in atomic units. A value other than null or 0 is only valid when the version 5 dApp script is invoked. The field is added in transaction version 3
сontinuationTransactionIds	List of the Continuation transactions in the computation sequence. The field is added in transaction version 3

The fields that are common to all types of transactions are described in the Transaction article.

# Binary Format

See the Invoke Script Transaction Binary Format article.

# Ride Structure

The InvokeScriptTransaction structure is used for transaction handling in smart contracts.