namillum

--- id: exchange-transaction-receipts title: Understanding Transaction Receipts keywords: - transaction receipts - fields - polling - exchanges - zilliqa description: Transaction Receipts Exchanges --- --- ## Transaction Receipts Confirmed transactions come with a **receipt** under the **result** field when [fetching the transaction](https://apidocs.zilliqa.com/#gettransaction) in JSON format. ## Basic Fields The following are the fields a **receipt** may have. These fields generally apply to both payment and contract transactions. | Field | Type | Description | | :----------------- | :------ | :------------------------------------------------------- | | **cumulative_gas** | string | The total gas consumed in this transaction | | **epoch_num** | string | The epoch number in which this transaction was confirmed | | **success** | boolean | The result of this transaction (`true` on success) | For example: ``` "receipt": { "cumulative_gas": "10481", "epoch_num": "586524", "success": true }, ``` ## Additional Fields For smart contract transactions, additional information relating to smart contract execution is contained in additional fields under the "**receipt**". ### Successful Transactions If a transaction is successful (i.e., the **success** field is `true`), these fields will be present: | Field | Type | Description | | :-------------- | :--------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **accepted** | boolean | Indicates whether the last transition in this transaction incurred a **balance transfer** | | **event_logs** | json-array | A list of event logs emitted by the contract during processing. Each log contains:<ol><li>**\_eventname**: [string] The name of the event</li><li>**address**: [string] The address of the contract that emitted this event</li><li>**params**: [json-array] A list of parameters under the transition. Each entry contains:<ul><li>**vname**: [string] The name of the variable</li><li>**type**: [string] The type of the variable</li><li>**value**: [string] The value of the variable</li></ul></li></ol> | | **transitions** | json-array | A list of internal transitions invoked during the processing of the transaction by the Scilla interpreter. Each transition contains:<ol><li>**addr**: [string] The address of the contract account that emitted this transition</li><li>**depth**: [int] The depth of the current transition. The transitions directly emitted by the recipient in the transaction will be in depth 0. If those transitions in depth 0 invoked transitions from other contracts, those will be in depth 1. And so on and so forth.</li><li>**msg**: [json-object] The message field emitted by the Scilla interpreter, which includes:<ul><li>**\_amount**: [string] The balance transferred from this transition</li><li>**\_recipient**: [string] The recipient of this transition, which can either be a wallet account or contract account</li><li>**\_tag**: [string] The contract-defined transition name</li><li>**params**: [json-array] A list of parameters under the transition. Each entry contains:<ul><li>**vname**: [string] The name of the variable</li><li>**type**: [string] The type of the variable</li><li>**value**: [string] The value of the variable</li></ul></li></ul></li></ol> | For example: ``` "receipt": { "accepted": true, "cumulative_gas": "878", "epoch_num": "589742", "event_logs":[ { "_eventname":"RecordsSet", "address":"0x708bfbba57436ed45efc13df9fab4249a354e06b", "params":[ { "type":"ByStr20", "value":"0x9611c53be6d1b32058b2747bdececed7e1216793", "vname":"registry" }, { "type":"ByStr32", "value":"0x2bb13c9b0a5dd28d42b470e2073df14608a9056310988b84b24dc342211e0627", "vname":"node" } ] }, ], "success": true, "transitions": [ { "addr": "0x9a65df55b2668a0f9f5f749267cb351a37e1f3d9", "depth": 0, "msg": { "_amount": "50000000000000", "_recipient": "0xc0e28525e9d329156e16603b9c1b6e4a9c7ed813", "_tag": "onFundsReceived", "params": [ "vname": "emp_addr", "type": "ByStr20", "Value": "0x00345678901234567890123456789012345678ab" ] } } ] } ``` ### Unsuccessful Transactions If a transaction is unsuccessful (i.e., the **success** field is `false`), no balance transfer will be executed. Additionally, these fields will be present: | Field | Type | Description | | :------------- | :---------- | :--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **errors** | json-object | An object containing a key-value field. The key [string] indicates the depth at which the error occurred. The value part is a JSON array that lists the error codes [int] reported. The list of possible error codes can be found [here](https://github.com/Zilliqa/Zilliqa/blob/8b088f8ea63f1aab43fde8bbb9741ecaf36b089b/src/libData/AccountData/TransactionReceipt.h#L32). | | **exceptions** | json-array | A list of exceptions returned by the Scilla interpreter. Each exception contains:<ol><li>**line”**: [int] The line in the Scilla contract code where the exception was detected</li><li>**message**: [string] The message describing the exception</li></ol> | For example: ``` "receipt": { "cumulative_gas": "1220", "epoch_num": "588004", "errors": { "0": [ 7 ] }, "exceptions": [ { "line": 87, "message": "Exception thrown: (Message [(_exception : (String \"Error\")) ; (code : (Int32 -2))])" }, { "line": 100, "message": "Raised from IsAdmin" }, { "line": 137, "message": "Raised from ConfigureUsers" } ], "success": false } ``` ## Recommended Steps for Exchanges Polling for Incoming $ZIL Deposit from Smart Contract Transactions 1. Confirm that the **success** field is set to `true`. 1. Traverse the **transitions** JSON array. For each transition, for a successful deposit of `$ZIL` via the smart contract, the following must be fulfilled: 1. **\_recipient** corresponds to a known deposit address controlled by the exchange. 2. **\_tag** is either `AddFunds` or empty. :::note `_tag` can be found under `msg` field. If either `_tag` or `msg` is not present, there is no incoming deposit from this particular transition. ::: 3. **\_amount** is non-zero. 4. Check the **\_recipient** and **\_amount** to complete the information on the balance transfer. In such a case, you can confirm that there is a deposit to address **\_recipient** with value **\_amount** (in `Qa`). 5. Continue traversing the remaining transitions and checking for more deposits.