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

# Simulate a card authorization advice

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

## 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_advice`
- Auth: HTTP basic

Simulate an `AUTHORIZATION_ADVICE` that re-sizes an existing open authorization on a `CardTransaction` in the sandbox environment. The `amount` is the new *total* authorized amount the advice re-sizes to. The parent transaction must be in `AUTHORIZED` or `PARTIALLY_SETTLED` state. The resulting card operation is delivered asynchronously via the issuer's events webhook.

Production returns `404` on this path.

## Path parameters

- `id` string, required

## Request body

- SandboxCardAuthorizationAdviceRequest: Sandbox-only request body for `POST /sandbox/cards/{id}/simulate/authorization_advice`. Drives an `AUTHORIZATION_ADVICE` that re-sizes an existing open authorization.
  - `cardTransactionId` string, required: The id of the `CardTransaction` the advice re-sizes. Must be in `AUTHORIZED` or `PARTIALLY_SETTLED` state.
  - `amount` integer, required: The new *total* authorized amount, in the smallest unit of the transaction's currency, that the advice re-sizes the authorization to.

## 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
- `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_advice/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)