> ## Documentation Index > Fetch the complete documentation index at: https://docs.lightspark.com/llms.txt > Use this file to discover all available pages before exploring further. # Simulate a card financial authorization > Simulate a single-message financial authorization (an authorization that clears in the same message, e.g. an ATM withdrawal or other dual-message-exempt flow) against a card 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. ## OpenAPI ````yaml https://app.stainless.com/api/spec/documented/grid/openapi.documented.yml post /sandbox/cards/{id}/simulate/financial_authorization openapi: 3.1.0 info: title: Grid API description: > API for managing global payments on the open Money Grid. Built by Lightspark. See the full documentation at https://docs.lightspark.com/. version: '2025-10-13' contact: name: Lightspark Support email: support@lightspark.com license: name: Proprietary url: https://lightspark.com/terms servers: - url: https://api.lightspark.com/grid/2025-10-13 description: Production server security: - BasicAuth: [] - AgentAuth: [] tags: - name: Platform Configuration description: >- Platform configuration endpoints for managing global settings. You can also configure these settings in the Grid dashboard. - name: Customers description: >- Customer management endpoints for creating and updating customer information - name: Contact Verification description: >- Endpoints for verifying a customer's email and phone via one-time codes. Required only for customers whose payment provider mandates contact verification (e.g. EU customers); other providers return 409. - name: Strong Customer Authentication description: >- Endpoints for authorizing money-movement operations that require Strong Customer Authentication. Relevant only for customers in a region where SCA is required (e.g. EU); customers outside SCA-regulated regions never see an SCA challenge and these endpoints return 409. - name: KYC/KYB Verifications description: >- Endpoints for Know Your Customer (KYC) and Know Your Business (KYB) verification, including managing beneficial owners and triggering verification for customers. - name: Documents description: >- Endpoints for uploading and managing verification documents for customers and beneficial owners. Supports KYC and KYB document requirements. - name: Internal Accounts description: >- Internal account management endpoints for creating and managing internal accounts - name: External Accounts description: >- External account management endpoints for creating and managing external bank accounts - name: Same-Currency Transfers description: >- Endpoints for transferring funds between internal and external accounts with the same currency - name: Cross-Currency Transfers description: Endpoints for creating and confirming quotes for cross-currency transfers - name: Transactions description: Endpoints for retrieving transaction information - name: Webhooks description: Webhook endpoints and configuration for receiving notifications - name: Invitations description: Endpoints for creating, claiming and managing UMA invitations - name: Sandbox description: Endpoints to trigger test cases in sandbox - name: API Tokens description: Endpoints to programmatically manage API tokens - name: Exchange Rates description: >- Endpoints for retrieving cached foreign exchange rates. Rates are cached for approximately 5 minutes and include platform-specific fees. - name: Discoveries description: >- Endpoints for discovering available payment rails, banks, and providers for a given country and currency corridor. - name: Embedded Wallet Auth description: >- Endpoints for registering and verifying end-user authentication credentials (email OTP, OAuth, passkey) used to sign Embedded Wallet actions. - name: Agent Management description: >- Endpoints for creating and managing agents (experimental), called by the partner's backend using platform credentials. Covers the full agent lifecycle: creation, policy configuration, pausing, deletion, the device code installation flow, and approving or rejecting transactions initiated by agents. - name: Agent Operations description: >- Endpoints called by the agent itself using its own credentials (obtained via device code redemption). Scoped to the agent's associated customer — all requests automatically operate on behalf of that customer and are subject to the agent's policy. When an action requires approval, the resulting transaction enters a pending state and must be approved by the platform via `POST /transactions/{transactionId}/approve`. - name: Cards description: >- Card management endpoints. Issue debit cards against an internal account, freeze / unfreeze, close, manage card funding sources, and list card transactions. - name: Stablecoins description: >- Stablecoin issuance endpoints. Link provider accounts, register provider-created stablecoins, create mint/burn quotes, execute them, and track the resulting operations. paths: /sandbox/cards/{id}/simulate/financial_authorization: post: tags: - Sandbox summary: Simulate a card financial authorization description: > Simulate a single-message financial authorization (an authorization that clears in the same message, e.g. an ATM withdrawal or other dual-message-exempt flow) against a card 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. operationId: sandboxSimulateCardFinancialAuthorization parameters: - name: id in: path required: true description: The id of the card to simulate a financial authorization against. schema: type: string example: Card:019542f5-b3e7-1d02-0000-000000000010 requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/SandboxCardAuthorizationRequest' examples: financialAuth: summary: $80.00 single-message ATM withdrawal value: amount: 8000 currency: code: USD merchant: descriptor: ATM WITHDRAWAL 24TH ST mcc: '6011' country: US responses: '202': description: >- 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. content: application/json: schema: $ref: '#/components/schemas/SandboxCardSimulationResponse' '400': description: Bad request - Invalid parameters content: application/json: schema: $ref: '#/components/schemas/Error400' '401': description: Unauthorized content: application/json: schema: $ref: '#/components/schemas/Error401' '403': description: Forbidden - request was made with a production platform token content: application/json: schema: $ref: '#/components/schemas/Error403' '404': description: Card not found (also returned in production for this path) content: application/json: schema: $ref: '#/components/schemas/Error404' '500': description: Internal service error content: application/json: schema: $ref: '#/components/schemas/Error500' security: - BasicAuth: [] components: schemas: SandboxCardAuthorizationRequest: type: object required: - amount - currency - merchant description: >- 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. properties: amount: type: integer format: int64 description: >- Authorization amount in the smallest unit of `currency` (e.g. cents for USD). exclusiveMinimum: 0 example: 1250 currency: $ref: '#/components/schemas/Currency' merchant: $ref: '#/components/schemas/CardMerchant' SandboxCardSimulationResponse: type: object required: - issuerTransactionToken description: >- 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. properties: issuerTransactionToken: type: string description: >- 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 Error400: type: object required: - message - status - code properties: status: type: integer enum: - 400 description: HTTP status code code: type: string description: > | Error Code | Description | |------------|-------------| | INVALID_INPUT | Invalid input provided | | MISSING_MANDATORY_USER_INFO | Required customer information is missing | | INVITATION_ALREADY_CLAIMED | Invitation has already been claimed | | INVITATIONS_NOT_CONFIGURED | Invitations are not configured | | INVALID_UMA_ADDRESS | UMA address format is invalid | | INVITATION_CANCELLED | Invitation has been cancelled | | QUOTE_REQUEST_FAILED | An issue occurred during the quote process; this is retryable | | INVALID_PAYREQ_RESPONSE | Counterparty Payreq response was invalid | | INVALID_RECEIVER | Receiver is invalid | | PARSE_PAYREQ_RESPONSE_ERROR | Error parsing receiver PayReq response | | CERT_CHAIN_INVALID | Counterparty certificate chain is invalid | | CERT_CHAIN_EXPIRED | Counterparty certificate chain has expired | | INVALID_PUBKEY_FORMAT | Counterparty Public key format is invalid | | MISSING_REQUIRED_UMA_PARAMETERS | Counterparty required UMA parameters are missing | | SENDER_NOT_ACCEPTED | Sender is not accepted | | AMOUNT_OUT_OF_RANGE | Amount is out of range | | INVALID_CURRENCY | Currency is invalid | | INVALID_TIMESTAMP | Timestamp is invalid | | INVALID_NONCE | Nonce is invalid | | INVALID_REQUEST_FORMAT | Request format is invalid | | INVALID_BANK_ACCOUNT | Bank account is invalid | | SELF_PAYMENT | Self payment not allowed | | LOOKUP_REQUEST_FAILED | Lookup request failed | | PARSE_LNURLP_RESPONSE_ERROR | Error parsing LNURLP response | | INVALID_AMOUNT | Amount is invalid | | WEBHOOK_ENDPOINT_NOT_SET | Webhook endpoint is not set | | WEBHOOK_DELIVERY_ERROR | Webhook delivery error | | LOW_QUALITY | Document quality too low to process | | DATA_MISMATCH | Document details don't match provided information | | EXPIRED | Document has expired | | SUSPECTED_FRAUD | Document suspected of being forged or edited | | UNSUITABLE_DOCUMENT | Document type is not accepted or not supported | | INCOMPLETE | Document is missing pages or sides | | EMAIL_OTP_CREDENTIAL_ALREADY_EXISTS | An EMAIL_OTP credential is already registered on the target internal account; only one email OTP credential is supported per internal account at this time | | SMS_OTP_CREDENTIAL_ALREADY_EXISTS | An SMS_OTP credential is already registered on the target internal account; only one SMS OTP credential is supported per internal account at this time | | PASSKEY_CREDENTIAL_ALREADY_EXISTS | A PASSKEY credential with the same WebAuthn credentialId is already registered on the target internal account | | STABLECOIN_PROVIDER_ACCOUNT_INVALID | The stablecoin provider account link is not usable | | STABLECOIN_PROVIDER_ACCOUNT_REVOKED | The stablecoin provider account link has been revoked | | STABLECOIN_PROVIDER_ACCOUNT_SELECTION_REQUIRED | Multiple active provider account links exist; pass `stablecoinProviderAccountId` to select one | enum: - INVALID_INPUT - MISSING_MANDATORY_USER_INFO - INVITATION_ALREADY_CLAIMED - INVITATIONS_NOT_CONFIGURED - INVALID_UMA_ADDRESS - INVITATION_CANCELLED - QUOTE_REQUEST_FAILED - INVALID_PAYREQ_RESPONSE - INVALID_RECEIVER - PARSE_PAYREQ_RESPONSE_ERROR - CERT_CHAIN_INVALID - CERT_CHAIN_EXPIRED - INVALID_PUBKEY_FORMAT - MISSING_REQUIRED_UMA_PARAMETERS - SENDER_NOT_ACCEPTED - AMOUNT_OUT_OF_RANGE - INVALID_CURRENCY - INVALID_TIMESTAMP - INVALID_NONCE - INVALID_REQUEST_FORMAT - INVALID_BANK_ACCOUNT - SELF_PAYMENT - LOOKUP_REQUEST_FAILED - PARSE_LNURLP_RESPONSE_ERROR - INVALID_AMOUNT - WEBHOOK_ENDPOINT_NOT_SET - WEBHOOK_DELIVERY_ERROR - LOW_QUALITY - DATA_MISMATCH - EXPIRED - SUSPECTED_FRAUD - UNSUITABLE_DOCUMENT - INCOMPLETE - EMAIL_OTP_CREDENTIAL_ALREADY_EXISTS - SMS_OTP_CREDENTIAL_ALREADY_EXISTS - PASSKEY_CREDENTIAL_ALREADY_EXISTS - STABLECOIN_PROVIDER_ACCOUNT_INVALID - STABLECOIN_PROVIDER_ACCOUNT_REVOKED - STABLECOIN_PROVIDER_ACCOUNT_SELECTION_REQUIRED message: type: string description: Error message details: type: object description: Additional error details additionalProperties: true Error401: type: object required: - message - status - code properties: status: type: integer enum: - 401 description: HTTP status code code: type: string description: > | Error Code | Description | |------------|-------------| | UNAUTHORIZED | Issue with API credentials | | INVALID_SIGNATURE | Signature header is invalid | | WALLET_SIGNATURE_MISSING | The `Grid-Wallet-Signature` header is required for this Embedded Wallet action but was not supplied | | WALLET_SIGNATURE_MALFORMED | The `Grid-Wallet-Signature` header could not be parsed (bad encoding, structure, or fields) | | WALLET_SIGNATURE_BODY_MISMATCH | The `Grid-Wallet-Signature` was computed over a different request body than the one received | | WALLET_SIGNATURE_INVALID | The `Grid-Wallet-Signature` failed cryptographic verification against the registered credential | | REQUEST_ID_MISSING | The `Request-Id` header is required on the signed retry but was not supplied (paired with `Grid-Wallet-Signature`) | enum: - UNAUTHORIZED - INVALID_SIGNATURE - WALLET_SIGNATURE_MISSING - WALLET_SIGNATURE_MALFORMED - WALLET_SIGNATURE_BODY_MISMATCH - WALLET_SIGNATURE_INVALID - REQUEST_ID_MISSING message: type: string description: Error message details: type: object description: Additional error details additionalProperties: true Error403: type: object required: - message - status - code properties: status: type: integer enum: - 403 description: HTTP status code code: type: string description: > | Error Code | Description | |------------|-------------| | FORBIDDEN | Insufficient permissions | | USER_NOT_READY | Customer exists but is not ready for operation | | COUNTERPARTY_NOT_ALLOWED | Counterparty has not been enabled for your account | | VELOCITY_LIMIT_EXCEEDED | Counterparty has exceeded velocity limits | enum: - FORBIDDEN - USER_NOT_READY - COUNTERPARTY_NOT_ALLOWED - VELOCITY_LIMIT_EXCEEDED message: type: string description: Error message details: type: object description: Additional error details additionalProperties: true Error404: type: object required: - message - status - code properties: status: type: integer enum: - 404 description: HTTP status code code: type: string description: > | Error Code | Description | |------------|-------------| | TRANSACTION_NOT_FOUND | Transaction not found | | INVITATION_NOT_FOUND | Invitation not found | | USER_NOT_FOUND | Customer not found | | QUOTE_NOT_FOUND | Quote not found | | LOOKUP_REQUEST_NOT_FOUND | Lookup request not found | | TOKEN_NOT_FOUND | Token not found | | BULK_UPLOAD_JOB_NOT_FOUND | Bulk upload job not found | | REFERENCE_NOT_FOUND | Reference not found | | UMA_NOT_FOUND | The UMA address is well-formed but no receiver exists at the counterparty VASP | | STABLECOIN_PROVIDER_ACCOUNT_NOT_FOUND | Stablecoin provider account link not found | enum: - TRANSACTION_NOT_FOUND - INVITATION_NOT_FOUND - USER_NOT_FOUND - QUOTE_NOT_FOUND - LOOKUP_REQUEST_NOT_FOUND - TOKEN_NOT_FOUND - BULK_UPLOAD_JOB_NOT_FOUND - REFERENCE_NOT_FOUND - UMA_NOT_FOUND - STABLECOIN_PROVIDER_ACCOUNT_NOT_FOUND message: type: string description: Error message details: type: object description: Additional error details additionalProperties: true Error500: type: object required: - message - status - code properties: status: type: integer enum: - 500 description: HTTP status code code: type: string description: | | Error Code | Description | |------------|-------------| | GRID_SWITCH_ERROR | Grid switch error | | INTERNAL_ERROR | Internal server or UMA error | enum: - GRID_SWITCH_ERROR - INTERNAL_ERROR message: type: string description: Error message details: type: object description: Additional error details additionalProperties: true Currency: type: object properties: code: type: string description: >- Three-letter currency code (ISO 4217) for fiat currencies. Some cryptocurrencies may use their own ticker symbols (e.g. "BTC" for Bitcoin, "USDC" for USDC, etc.) example: USD name: type: string description: Full name of the currency example: United States Dollar symbol: type: string description: Symbol of the currency example: $ decimals: type: integer description: Number of decimal places for the currency minimum: 0 example: 2 CardMerchant: type: object required: - descriptor properties: descriptor: type: string description: >- Merchant descriptor string captured from the card network at authorization time. example: BLUE BOTTLE COFFEE SF mcc: type: string description: Merchant Category Code (ISO 18245) — four-digit numeric string. example: '5814' country: type: string description: Two-letter ISO 3166-1 alpha-2 country code of the merchant. example: US securitySchemes: BasicAuth: type: http scheme: basic description: >- API token authentication using format `:` AgentAuth: type: http scheme: bearer description: >- Bearer token authentication for agent-scoped endpoints. The token is the `accessToken` returned when redeeming a device code via `POST /agents/device-codes/{code}/redeem`. Agent credentials are user-scoped: all requests are automatically bound to the agent's associated customer and subject to the agent's policy. ````