---
title: "Simulate a card authorization reversal"
method: POST
path: "/sandbox/cards/{id}/simulate/authorization_reversal"
tags: ["Sandbox"]
---

# Simulate a card authorization reversal

`POST /sandbox/cards/{id}/simulate/authorization_reversal`

## Request

- Base URL: `https://api.lightspark.com/grid/2025-10-13`
- URL: `https://api.lightspark.com/grid/2025-10-13/sandbox/cards/{id}/simulate/authorization_reversal`
- Auth: HTTP basic

Simulate a merchant cancelling a card authorization before it settles — a hotel releasing a hold, or a store voiding a purchase that never went through. Use it to see how your integration handles an authorization that disappears without ever clearing.
Send `amount` to reverse only part of the authorization, or leave it out to reverse all of it. The transaction must still be fully open: once any part of it has settled, it can no longer be reversed.
Grid processes the reversal in the background. A full reversal sets `status: VOIDED` and sends a `CARD_TRANSACTION.VOIDED` webhook. A partial reversal leaves the transaction `AUTHORIZED` with a smaller hold.

Production returns `404` on this path.

## Path parameters

- `id` string, required

## Request body

- SandboxCardReversalRequest: Request body for `POST /sandbox/cards/{id}/simulate/authorization_reversal`: which authorization to reverse, and optionally how much of it.
  - `cardTransactionId` string, required: The authorization to reverse. It must still be fully open, with nothing settled against it yet.
  - `amount` integer: How much to reverse, in the smallest unit of the transaction's currency (cents for USD). Leave it out to reverse the whole authorization. Send an amount to reverse only that much and leave the rest on hold.

## Response `202`

Simulation accepted. The resulting card operation is delivered asynchronously via the issuer's events webhook. Returns the issuer transaction token that correlates the simulated event.

- SandboxCardSimulationResponse: Response body for the sandbox card-event simulators. The simulate call pokes the card issuer's sandbox; the resulting card operation is delivered asynchronously via the issuer's events webhook, never synchronously in this response.
  - `issuerTransactionToken` string, required: The card issuer's transaction token for the simulated event. Correlates the eventual webhook-delivered card operation back to this simulate call.

## Other responses

- `400`: Bad request - Invalid parameters, or the transaction is not an open authorization
- `401`: Unauthorized
- `403`: Forbidden - request was made with a production platform token
- `404`: Card or card transaction not found
- `409`: Conflict. The simulation targets a card in a program where the card issuer makes authorization decisions. These sandbox simulators support only card programs where Grid makes authorization decisions. This is a property of the card's program, so retrying will not help.
- `500`: Internal service error

## Changes

> 115 revisions in range; 2 not diffed.

- **2026-10-28** `d996ddfb9d2b`: 5 info
  - added the optional property `details/missingFields` to the response with the `400` status
  - added the optional property `details/permission` to the response with the `403` status
  - added the optional property `details/policyDenialReason` to the response with the `403` status
  - added the optional property `details/refusalReason` to the response with the `400` status
  - …1 more
- **2026-10-28** `5abf2bb56bcb`: 1 warning
  - added the new `CORRIDOR_UNDER_MAINTENANCE` enum value to the `code` response property for the response status `403`
- **2026-10-26** `f11f1e76bdd7`: 1 warning
  - added the new `PURCHASE_CARD_LIMIT_REACHED` enum value to the `code` response property for the response status `409`
- **2026-10-26** `0a6dad5815c7`: 1 warning
  - added the new `INVOICE_ALREADY_USED` enum value to the `code` response property for the response status `409`
- **2026-10-24** `715332dcb111`: 1 warning
  - added the new `EXACT_AMOUNT_UNAVAILABLE` enum value to the `code` response property for the response status `400`

[Operation history](https://skmtc.dev/lightsparkdev/apis/grid-api/changes/sandbox/cards/:id/simulate/authorization_reversal/post.md)

---

[API](https://skmtc.dev/lightsparkdev/apis/grid-api.md) - [All operations](https://skmtc.dev/lightsparkdev/apis/grid-api/llms.txt) - [OpenAPI document](https://skmtc.dev/lightsparkdev/apis/grid-api/revisions/7a1db46ec552?raw)