Simulate a card credit authorization

curl --request POST \
  --url https://api.lightspark.com/grid/2025-10-13/sandbox/cards/{id}/simulate/credit_authorization \
  --header 'Authorization: Basic <encoded-value>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "amount": 2500,
  "currency": {
    "code": "USD"
  },
  "merchant": {
    "descriptor": "ACME MARKETPLACE",
    "mcc": "5942",
    "country": "US"
  }
}
'

const options = {
  method: 'POST',
  headers: {Authorization: 'Basic <encoded-value>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    amount: 2500,
    currency: {code: 'USD'},
    merchant: {descriptor: 'ACME MARKETPLACE', mcc: '5942', country: 'US'}
  })
};

fetch('https://api.lightspark.com/grid/2025-10-13/sandbox/cards/{id}/simulate/credit_authorization', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

val client = OkHttpClient()

val mediaType = MediaType.parse("application/json")
val body = RequestBody.create(mediaType, "{\n  \"amount\": 2500,\n  \"currency\": {\n    \"code\": \"USD\"\n  },\n  \"merchant\": {\n    \"descriptor\": \"ACME MARKETPLACE\",\n    \"mcc\": \"5942\",\n    \"country\": \"US\"\n  }\n}")
val request = Request.Builder()
  .url("https://api.lightspark.com/grid/2025-10-13/sandbox/cards/{id}/simulate/credit_authorization")
  .post(body)
  .addHeader("Authorization", "Basic <encoded-value>")
  .addHeader("Content-Type", "application/json")
  .build()

val response = client.newCall(request).execute()

{
  "issuerTransactionToken": "f3a1c2d4-5b6e-7890-abcd-ef0123456789"
}

{
  "status": 400,
  "message": "<string>",
  "details": {}
}

{
  "status": 401,
  "message": "<string>",
  "details": {}
}

{
  "status": 403,
  "message": "<string>",
  "details": {}
}

{
  "status": 404,
  "message": "<string>",
  "details": {}
}

{
  "status": 500,
  "message": "<string>",
  "details": {}
}

Sandbox

Simulate a card credit authorization

Simulate an inbound credit authorization (a merchant-initiated credit to the card, e.g. a refund pushed as an authorization) in the sandbox environment. Drives the same internal paths the card issuer would call in production. The resulting card operation is delivered asynchronously via the issuer’s events webhook.

As with simulate/authorization, the decisioning outcome is controlled by the last three characters of merchant.descriptor — see the simulate/authorization suffix table.

Production returns 404 on this path.

POST

sandbox

cards

{id}

simulate

credit_authorization

Simulate a card credit authorization

curl --request POST \
  --url https://api.lightspark.com/grid/2025-10-13/sandbox/cards/{id}/simulate/credit_authorization \
  --header 'Authorization: Basic <encoded-value>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "amount": 2500,
  "currency": {
    "code": "USD"
  },
  "merchant": {
    "descriptor": "ACME MARKETPLACE",
    "mcc": "5942",
    "country": "US"
  }
}
'

const options = {
  method: 'POST',
  headers: {Authorization: 'Basic <encoded-value>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    amount: 2500,
    currency: {code: 'USD'},
    merchant: {descriptor: 'ACME MARKETPLACE', mcc: '5942', country: 'US'}
  })
};

fetch('https://api.lightspark.com/grid/2025-10-13/sandbox/cards/{id}/simulate/credit_authorization', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

val client = OkHttpClient()

val mediaType = MediaType.parse("application/json")
val body = RequestBody.create(mediaType, "{\n  \"amount\": 2500,\n  \"currency\": {\n    \"code\": \"USD\"\n  },\n  \"merchant\": {\n    \"descriptor\": \"ACME MARKETPLACE\",\n    \"mcc\": \"5942\",\n    \"country\": \"US\"\n  }\n}")
val request = Request.Builder()
  .url("https://api.lightspark.com/grid/2025-10-13/sandbox/cards/{id}/simulate/credit_authorization")
  .post(body)
  .addHeader("Authorization", "Basic <encoded-value>")
  .addHeader("Content-Type", "application/json")
  .build()

val response = client.newCall(request).execute()

{
  "issuerTransactionToken": "f3a1c2d4-5b6e-7890-abcd-ef0123456789"
}

{
  "status": 400,
  "message": "<string>",
  "details": {}
}

{
  "status": 401,
  "message": "<string>",
  "details": {}
}

{
  "status": 403,
  "message": "<string>",
  "details": {}
}

{
  "status": 404,
  "message": "<string>",
  "details": {}
}

{
  "status": 500,
  "message": "<string>",
  "details": {}
}

Authorizations

Authorization

string

header

required

API token authentication using format <api token id>:<api client secret>

Path Parameters

string

required

The id of the card to simulate a credit authorization against.

Body

application/json

Sandbox-only request body shared by the card authorization-family simulate endpoints: simulate/authorization, simulate/credit_authorization, simulate/financial_authorization, simulate/financial_credit_authorization, and simulate/credit_authorization_advice. Drives the same internal authorization + reconcile paths that the issuer would call in production. The decisioning outcome is controlled by the last three characters of merchant.descriptor — see the simulate/authorization documentation for the suffix table.

amount

integer<int64>

required

Authorization amount in the smallest unit of currency (e.g. cents for USD).

Example:

1250

currency

object

required

Show child attributes

merchant

object

required

Show child attributes

Response

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.

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.

Example:

"f3a1c2d4-5b6e-7890-abcd-ef0123456789"

Simulate a card balance inquiry

Simulate a card financial authorization

⌘I

Using the API

API documentation

Simulate a card credit authorization

Authorizations

Path Parameters

Body

Response