POST

Simulate an underwriting decision

ENDPOINT/v1/simulate/applications/{application_id}/decision

Applies an underwriting decision to a sandbox application without waiting on the bureau or underwriter. APPROVED requires decision. Applications that are already terminal reject this transition. Served only on the sandbox host.

Authentication & Headers

Header	Type	Requirement	Description
Authorization	string	REQUIRED	API key passed as an HTTP Bearer token: `Bearer rk_live_...`
X-Program-ID	UUID	PROGRAM-SCOPED	Program boundary UUID that scopes the issuing card, wallet, or transfer.
Content-Type	string	REQUIRED	Must be `application/json`.
Idempotency-Key	string	OPTIONAL	Unique UUID to prevent duplicate execution of financial creations or mutations.

Path Parameters

Parameter	Type	Requirement	Description
application_id	string	REQUIRED	Unique identifier of the application.

Request Body Schema

application/json

statusstring

REQUIRED

Underwriting outcome to apply to a sandbox application. `APPROVED` sets application `status` `APPROVED` and fills `decision`. `DECLINED` sets `status` `DECLINED`.

Enum values:APPROVEDDECLINED

decisionobject

optional

Underwriting outcome on an approved or declined application. Null on the application while `status` is `RECEIVED`, `IN_REVIEW`, `PENDING_DOCUMENTS`, or `WITHDRAWN`.

Properties of decision

credit_limitobjectrequired

Approved credit limit. `amount` is a non-negative integer of minor units; `500000` with `USD` is $5,000.00. Zero when declined.

aprintegerrequired

Purchase APR in basis points on an approval. `2499` is 24.99%. Zero when declined.

reasonsarrayrequired

Machine-readable reasons for the decision. Empty on a clean approval.

Response Codes & Schemas

200The application after the decision.

application/json

{
  "id": "6a0d5e28-1f4b-4c79-a3d6-8e2b9c7f0154",
  "object": "application",
  "status": "APPROVED",
  "wallet_entity_id": "2e9c4b71-8a5d-4f03-b6e2-1c7d9a0f3e58",
  "program_id": "7c9e6679-7425-40de-944b-e07fc1f90ae7",
  "product_id": "3f0c7a12-5d8e-4a91-b6c2-9e1f0a4d7c33",
  "requested_credit_limit": {
    "amount": 500000,
    "currency": "USD"
  },
  "income": {
    "amount": 8500000,
    "currency": "USD"
  },
  "consents": {
    "credit_check": true,
    "electronic_communications": true,
    "cardholder_agreement": true,
    "privacy_policy": true
  },
  "decision": {
    "credit_limit": {
      "amount": 500000,
      "currency": "USD"
    },
    "apr": 2499,
    "reasons": [
      "APPROVED"
    ]
  },
  "kyc": {
    "status": "PASSED",
    "checks": [
      {
        "name": "CIP",
        "status": "PASSED"
      },
      {
        "name": "OFAC",
        "status": "PASSED"
      },
      {
        "name": "KYC",
        "status": "PASSED"
      },
      {
        "name": "KYB",
        "status": "NOT_APPLICABLE"
      },
      {
        "name": "IDV",
        "status": "PASSED"
      },
      {
        "name": "CREDIT",
        "status": "PASSED"
      }
    ]
  },
  "created_at": "2026-08-12T10:25:00Z",
  "updated_at": "2026-08-12T14:10:00Z"
}

400Bad Request: malformed JSON, failed schema validation, or conflicting parameters.

application/json

{
  "error": {
    "type": "invalid_request_error",
    "code": "invalid_request",
    "message": "invalid order by: foo. Valid options are: [created_at updated_at]",
    "param": "order_by",
    "request_id": "550e8400-e29b-41d4-a716-446655440000",
    "doc_url": "https://docs.rookpayments.com/errors/invalid_request"
  }
}

401Unauthorized: missing, malformed, or unknown API key.

application/json

{
  "error": {
    "type": "authentication_error",
    "code": "authentication_error",
    "message": "A valid API key is required.",
    "param": null,
    "request_id": "550e8400-e29b-41d4-a716-446655440000",
    "doc_url": "https://docs.rookpayments.com/errors/authentication_error"
  }
}

403Forbidden: the API key is denied by RBAC, or it cannot access this program. A resource that exists on another program or organization returns `404 not_found`, not `403`.

application/json

{
  "error": {
    "type": "permission_error",
    "code": "permission_denied",
    "message": "The API key cannot access this program.",
    "param": "X-Program-ID",
    "request_id": "550e8400-e29b-41d4-a716-446655440000",
    "doc_url": "https://docs.rookpayments.com/errors/permission_denied"
  }
}

404Not Found: unknown id, or the resource is not visible to this API key.

application/json

{
  "error": {
    "type": "not_found_error",
    "code": "not_found",
    "message": "No card found for the given id.",
    "param": "card_id",
    "request_id": "550e8400-e29b-41d4-a716-446655440000",
    "doc_url": "https://docs.rookpayments.com/errors/not_found"
  }
}

409Conflict: incompatible state, or Idempotency-Key reused with a different body.

application/json

{
  "error": {
    "type": "conflict_error",
    "code": "conflict",
    "message": "The card cannot be reissued from its current state.",
    "param": null,
    "request_id": "550e8400-e29b-41d4-a716-446655440000",
    "doc_url": "https://docs.rookpayments.com/errors/conflict"
  }
}

422Unprocessable Entity: the document is valid JSON but violates a business rule.

application/json

{
  "error": {
    "type": "invalid_request_error",
    "code": "insufficient_funds",
    "message": "The source financial account does not have enough available balance.",
    "param": "amount",
    "request_id": "550e8400-e29b-41d4-a716-446655440000",
    "doc_url": "https://docs.rookpayments.com/errors/insufficient_funds"
  }
}

429Too Many Requests: the API key exceeded its rate limit.

application/json

{
  "error": {
    "type": "rate_limit_error",
    "code": "rate_limited",
    "message": "Rate limit exceeded. Retry after the number of seconds in Retry-After.",
    "param": null,
    "request_id": "550e8400-e29b-41d4-a716-446655440000",
    "doc_url": "https://docs.rookpayments.com/errors/rate_limited"
  }
}

500Internal Server Error: unexpected failure. Retry with the same Idempotency-Key.

application/json

{
  "error": {
    "type": "api_error",
    "code": "internal_error",
    "message": "An unexpected error occurred. Retry with the same Idempotency-Key.",
    "param": null,
    "request_id": "550e8400-e29b-41d4-a716-446655440000",
    "doc_url": "https://docs.rookpayments.com/errors/internal_error"
  }
}