---
title: "DeclineCallback"
method: POST
path: "/DeclineCallback"
tags: ["Transactions"]
---

# DeclineCallback

`POST /DeclineCallback`

## Request body

- DeclineCallbackRequest, nullable — The request payload sent by Spark to the integrator's `/spark/DeclineCallback` endpoint to report a failed transaction.
  - `MachineId` integer — The unique ID of the vending machine or terminal where the transaction occurred.
  - `HwSerial` string — The serial number of the hardware terminal.
  - `SparkTransactionId` string, nullable — The unique identifier of the failed Spark transaction. This ID is typically generated during the `StartAuthentication` process.
  - `Status` Status — Transaction Status Details
    - `Verdict` string — Status of the request (Approved / Declined)
    - `ErrorCode` integer, nullable — - Conditional - Reason for declined request
    - `ErrorDescription` string, nullable — - Conditional - Length: 255 - Error description
    - `StatusMessage` string, nullable — - Optional - Length: 255 - Transaction status message as free text field

## Response `200`

Success. A simple 200 OK server acknowledgment is sufficient.

- DeclineCallbackOutcome, nullable — The response payload from the `DeclineCallback` endpoint, providing details about a failed Spark transaction. This payload confirms the transaction's failure and provides contextual information.
  - `SparkTransactionId` string, nullable — The unique identifier for the failed Spark transaction session. This ID is initially generated during the `StartAuthentication` process and is used to track the session throughout its lifecycle.
  - `Status` Status — Transaction Status Details
    - `Verdict` string — Status of the request (Approved / Declined)
    - `ErrorCode` integer, nullable — - Conditional - Reason for declined request
    - `ErrorDescription` string, nullable — - Conditional - Length: 255 - Error description
    - `StatusMessage` string, nullable — - Optional - Length: 255 - Transaction status message as free text field

---

[API](https://skmtc.net/nayax/apis/nayax-cortina-api.md) · [All operations](https://skmtc.net/nayax/apis/nayax-cortina-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/nayax/nayax-cortina-api/revisions/421f6f83c257/schema)