> ## Documentation Index > Fetch the complete documentation index at: https://docs.dakota.xyz/llms.txt > Use this file to discover all available pages before exploring further. # Simulate a card authorization > Presents a card authorization to Dakota as if a merchant had swiped the card. The authorization runs the production path: the authorization service decides it, the hold lands on the wallet, and the `card_transaction.created` webhook fires. Only the trigger is synthetic. A decline is a normal outcome, not an HTTP error. A card with too little spendable balance produces a `card_transaction` carrying the real decline result, so read the transaction rather than the status code to learn whether the authorization was approved. An authorization holds more than its own amount. The hold carries a buffer for network adjustments, so a 2 USD authorization needs about 2.60 USD of spendable balance. Fund the wallet with two faucet calls before you simulate a 2 USD purchase. The card must belong to a customer of the authenticated client. Available in sandbox mode only. ## OpenAPI ````yaml /openapi.yaml post /sandbox/cards/simulate/transaction openapi: 3.0.3 info: title: Dakota Platform API version: 1.0.0 description: >- Combined API specification for Dakota Platform services: - Issuance API: Asset minting and burning operations - Onboarding API: Know Your Business/Customer verification - On/Off Ramp API: Managing on-ramp and off-ramp accounts - Recipients API: Managing destinations for KYB'd entities - Transactions API: Viewing transaction history across platform operations ## Authentication and API Headers All API endpoints require the following headers: - `X-Idempotency-Key`: Required for all POST endpoints to ensure request idempotency - `x-api-key`: Required for authentication across all endpoints Note: On /applications endpoints you need a token for authentication instead of a x-api-key - `x-application-token`: Required for authentication on public /applications endpoints (alternative to `x-api-key` where documented) ## Rate Limits Requests are rate limited per API key. Every response includes the following headers: | Header | Description | | --- | --- | | `X-RateLimit-Limit` | Maximum requests allowed in the current one-minute window. | | `X-RateLimit-Remaining` | Requests remaining in the current window. | | `X-RateLimit-Reset` | Absolute Unix timestamp (seconds since epoch) when the current rate-limit window resets. | When a request is throttled (`429`), responses also include `Retry-After` with seconds to wait before retrying. servers: - url: https://api.platform.dakota.xyz description: Production environment - url: https://api.platform.sandbox.dakota.xyz description: Sandbox — safe for testing with simulated data security: - ApiKeyAuth: [] tags: - name: Agentic Payments x-beta: true description: >- Beta — agent-driven payments: provision agents, draft and approve spending mandates, accept reviewed instructions, and manage scheduled payments. **Prerequisites:** Customer onboarded; signer groups attached for recognition. **Related:** Wallets, Signer Groups, Transactions - name: Mandates x-beta: true description: >- Beta — spending mandates: signed, signer-bound authorizations governing what may be spent, approved or cancelled by a second recognized signer (§8 — the dual-control rule that every mandate mutation must be signed by a recognized signer OTHER than the bound one). Independent of agents and scheduled payments. **Prerequisites:** Signer groups attached for recognition. **Related:** Signer Groups, Transactions - name: Insights x-beta: true description: >- Beta — read-only insight: a deterministic report over a customer's agentic activity (funding balances, upcoming obligations, failures, mandate headroom and expiry), or — via `GET /insights` — over the whole client's book, with portfolio KPIs, daily series and a per-customer roll-up. Never moves money, never creates or changes anything. **Prerequisites:** Customer onboarded; insight is computed from the customer's scheduled payments, mandates, and wallets. **Related:** Agentic Payments, Mandates - name: Customers description: >- Manage customer entities representing businesses and organizations onboarded to Dakota. **Prerequisites:** Complete KYB via Onboarding endpoints before initiating money movement. **Related:** Onboarding, Recipients, Transactions, Accounts, Wallets - name: Wallets description: >- Manage wallets, balances, and wallet-to-signer-group relationships for custody and movement controls. **Prerequisites:** Customer must exist. Configure signer groups before policy-enforced workflows. **Related:** Signer Groups, Policies, Transactions, Customers - name: Transactions description: >- Create, cancel, and retrieve transaction records across account and wallet flows. **Prerequisites:** Accounts or destinations must be configured based on flow type. **Related:** Accounts, Recipients, Policies, Events - name: Recipients description: >- Manage recipient entities and destination rails used by customers for payouts and transfers. **Prerequisites:** Customer must be onboarded and active. **Related:** Customers, Transactions, Accounts, Onboarding - name: Accounts description: >- Manage account resources used for onramp, offramp, and swap operations. **Prerequisites:** Customer must be created and network/asset constraints must be known. **Related:** Customers, Transactions, Auto Transactions, Info - name: Auto Transactions description: >- Manage automated transaction configurations and execution history for account automation workflows. **Prerequisites:** Source account must exist and be configured for automation. **Related:** Accounts, Transactions, Events - name: Onboarding description: >- Manage KYB/KYC onboarding lifecycle, application documents, attestations, and verification steps. **Prerequisites:** Customer context and required entity/application metadata. **Related:** Customers, Exceptions, Recipients, Transactions - name: Policies description: >- Define and manage policy objects and rules used for transaction governance and risk controls. **Prerequisites:** Wallet and signer group resources should be configured for enforcement scenarios. **Related:** Wallets, Signer Groups, Transactions - name: Signer Groups description: >- Manage signer groups and signer assignments for multi-party authorization models. **Prerequisites:** Wallets should exist before linking signer groups. **Related:** Wallets, Policies, Transactions - name: Authentication description: >- Manage API authentication credentials and key lifecycle for platform access. **Prerequisites:** Client organization must be provisioned. **Related:** Users, Info - name: Users description: >- Manage client users, roles, and identity metadata for platform access control. **Prerequisites:** Auth credentials and client context must be established. **Related:** Authentication - name: Webhooks description: >- Manage outbound webhook targets and delivery configuration for event notifications. **Prerequisites:** Subscriber endpoint must be reachable and secured. **Related:** Events, Authentication - name: Payouts description: >- Manage where Dakota sends your accrued developer-fee payouts. **Prerequisites:** Auth credentials and client context must be established. **Related:** Events - name: RD Marketing Fee description: >- Everything behind your RD marketing fee: read what a month came to, declare the wallets you hold outside Dakota so the RD in them counts, and say where the fee should be sent. **Prerequisites:** Client must be in the RD marketing-fee programme. A month is readable once it has closed. **Related:** Wallets, Events - name: Self Serve description: >- Buy and track prepaid credits, and read the tiers and pricing they are sold at. **Prerequisites:** Auth credentials and client context must be established. **Related:** Billing - name: Events description: >- Retrieve event records emitted by platform operations for audit and troubleshooting. **Prerequisites:** Requesting client must have access to referenced resources. **Related:** Webhooks, Transactions, Onboarding - name: Info description: >- Read platform capability metadata, such as supported rails, networks, and assets. These operations are served under `/capabilities/*` - `GET /capabilities/countries` and `GET /capabilities/networks`. The tag name does not appear in the request paths. **Prerequisites:** Valid authentication headers. **Related:** Accounts, Transactions - name: Sandbox description: >- Trigger sandbox-only simulation endpoints for safe end-to-end integration testing with synthetic data. The sandbox host (`https://api.platform.sandbox.dakota.xyz`) also accepts a family of `X-Sandbox-*` request headers on most write endpoints (`Customers`, `Accounts`, `Transactions`, simulate endpoints) that let integrators drive deterministic failure modes — pick a preset via `X-Sandbox-Scenario`, or compose a custom one with `X-Sandbox-Error-Step`/`X-Sandbox-Error-Status`/`X-Sandbox-Error-Message`. `X-Sandbox-Instant-Completion` collapses async flows to a single synchronous step, and `X-Sandbox-Skip-Auto-Approval` keeps newly created KYB applications in `pending` for manual-review testing. All `X-Sandbox-*` headers are ignored in production. **Prerequisites:** Sandbox environment and test customer data. **Related:** Customers, Accounts, Transactions, Onboarding - name: Legal description: |- The legal documents customers accept — terms of service, privacy policy, e-sign notice, and partner agreements. Dakota publishes these here, and this is the authoritative source: the hosted onboarding flow, the dakota.xyz website, and your own integration all read the same revisions. Present the current revision to your customer before capturing their acceptance so the record reflects the text they actually saw. paths: /sandbox/cards/simulate/transaction: post: tags: - Sandbox summary: Simulate a card authorization description: | Presents a card authorization to Dakota as if a merchant had swiped the card. The authorization runs the production path: the authorization service decides it, the hold lands on the wallet, and the `card_transaction.created` webhook fires. Only the trigger is synthetic. A decline is a normal outcome, not an HTTP error. A card with too little spendable balance produces a `card_transaction` carrying the real decline result, so read the transaction rather than the status code to learn whether the authorization was approved. An authorization holds more than its own amount. The hold carries a buffer for network adjustments, so a 2 USD authorization needs about 2.60 USD of spendable balance. Fund the wallet with two faucet calls before you simulate a 2 USD purchase. The card must belong to a customer of the authenticated client. Available in sandbox mode only. operationId: simulateCardTransaction parameters: - $ref: '#/components/parameters/IdempotencyKeyHeader' requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/SandboxCardTransactionRequest' example: card_id: 1NFHrqBHb3cTfLVkFSGmHZqdDPi amount: '2.00' merchant: descriptor: COFFEE ROASTERS mcc: '5814' city: BROOKLYN state: NY country: USA type: authorization responses: '202': description: Card simulation accepted content: application/json: schema: $ref: '#/components/schemas/SandboxCardSimulationResponse' example: simulation_id: sim_card_01J8ZQ4T7K2M9X card_transaction_id: 2ZFHrqBHb3cTfLVkFSGmHZqdDPi status: completed '400': description: Invalid request content: application/problem+json: schema: $ref: '#/components/schemas/ProblemDetails' example: type: https://docs.dakota.xyz/api-reference/errors#invalid-request title: Invalid request status: 400 detail: >- amount must be a positive decimal with at most two decimal places instance: >- https://api.platform.dakota.xyz/sandbox/cards/simulate/transaction request_id: req_01hzy6y7v8w9x0y1z2a3b4c5d6 '403': description: Not available outside sandbox mode content: application/problem+json: schema: $ref: '#/components/schemas/ProblemDetails' example: type: https://docs.dakota.xyz/api-reference/errors#forbidden title: Forbidden status: 403 detail: Endpoint only available in sandbox mode instance: >- https://api.platform.dakota.xyz/sandbox/cards/simulate/transaction request_id: req_01hzy6y7v8w9x0y1z2a3b4c5d6 '404': description: Card not found content: application/problem+json: schema: $ref: '#/components/schemas/ProblemDetails' example: type: https://docs.dakota.xyz/api-reference/errors#not-found title: Card not found status: 404 detail: Card not found instance: >- https://api.platform.dakota.xyz/sandbox/cards/simulate/transaction request_id: req_01hzy6y7v8w9x0y1z2a3b4c5d6 '409': description: | The card cannot present a transaction, the idempotency key was reused with different parameters, or the simulation under this idempotency key was abandoned before it recorded a result. The last one never resolves under the same key: retry it with a new `X-Idempotency-Key`. content: application/problem+json: schema: $ref: '#/components/schemas/ProblemDetails' example: type: https://docs.dakota.xyz/api-reference/errors#card-not-active title: Card Not Active status: 409 detail: The card must be active to present a simulated transaction. instance: >- https://api.platform.dakota.xyz/sandbox/cards/simulate/transaction request_id: req_01hzy6y7v8w9x0y1z2a3b4c5d6 '422': description: | Amount over the sandbox per-transaction cap, or a client that is not provisioned at the provider yet. content: application/problem+json: schema: $ref: '#/components/schemas/ProblemDetails' example: type: >- https://docs.dakota.xyz/api-reference/errors#sandbox-amount-cap-exceeded title: Sandbox Amount Cap Exceeded status: 422 detail: >- amount 25 exceeds sandbox cap of 2; reduce the amount and retry instance: >- https://api.platform.dakota.xyz/sandbox/cards/simulate/transaction request_id: req_01hzy6y7v8w9x0y1z2a3b4c5d6 '429': description: | The client has used its card-simulation allowance for the day. The allowance restores itself within 24 hours. content: application/problem+json: schema: $ref: '#/components/schemas/ProblemDetails' example: type: >- https://docs.dakota.xyz/api-reference/errors#sandbox-card-simulation-daily-limit title: Sandbox Card Simulation Daily Limit status: 429 detail: >- This client has used its card-simulation allowance for the day. Retry within 24 hours. instance: >- https://api.platform.dakota.xyz/sandbox/cards/simulate/transaction request_id: req_01hzy6y7v8w9x0y1z2a3b4c5d6 '500': description: Platform failed to process the request content: application/problem+json: schema: $ref: '#/components/schemas/ProblemDetails' example: type: https://docs.dakota.xyz/api-reference/errors#internal-error title: Internal Error status: 500 detail: An internal error occurred instance: >- https://api.platform.dakota.xyz/sandbox/cards/simulate/transaction request_id: req_01hzy6y7v8w9x0y1z2a3b4c5d6 '501': description: Card simulation is not enabled in this deployment content: application/problem+json: schema: $ref: '#/components/schemas/ProblemDetails' example: type: https://docs.dakota.xyz/api-reference/errors#not-implemented title: Not Implemented status: 501 detail: card simulation is not available in this deployment yet instance: >- https://api.platform.dakota.xyz/sandbox/cards/simulate/transaction request_id: req_01hzy6y7v8w9x0y1z2a3b4c5d6 '502': description: Provider gRPC call failed content: application/problem+json: schema: $ref: '#/components/schemas/ProblemDetails' example: type: https://docs.dakota.xyz/api-reference/errors#provider-error title: Provider Error status: 502 detail: provider sandbox service returned an error instance: >- https://api.platform.dakota.xyz/sandbox/cards/simulate/transaction request_id: req_01hzy6y7v8w9x0y1z2a3b4c5d6 externalDocs: description: Read full guide in docs url: >- https://docs.dakota.xyz/api-reference/sandbox/simulate-card-transactions components: parameters: IdempotencyKeyHeader: name: x-idempotency-key in: header required: true description: >- Unique key to ensure request idempotency. If the same key is used within a certain time window, the original response will be returned instead of executing the request again. schema: type: string format: uuid schemas: SandboxCardTransactionRequest: type: object description: A request to present a simulated authorization on a card. required: - card_id properties: card_id: $ref: '#/components/schemas/KSUID' amount: type: string description: | Amount in decimal USD, at most two decimal places. Capped by the sandbox per-transaction limit. Required for every `type` except `balance_inquiry`, which moves no funds and so takes no amount: omit it, or send `"0"`. A `balance_inquiry` naming a non-zero amount is refused. example: '2.00' merchant: $ref: '#/components/schemas/SandboxCardMerchant' type: type: string default: authorization description: | Which network message the simulation opens. `authorization` is a standard purchase; `financial_authorization` clears immediately; `balance_inquiry` checks the spendable balance and moves no funds, so it is the one type that takes no `amount`. enum: - authorization - credit_authorization - financial_authorization - balance_inquiry example: authorization partial_approval_capable: type: boolean description: | Whether the merchant accepts a partial approval. A merchant that does gets an approval for the available balance instead of a decline. SandboxCardSimulationResponse: type: object description: An accepted card simulation. required: - simulation_id - status properties: simulation_id: type: string description: | Simulation identifier. Resolve it with `GET /sandbox/simulations/{simulation_id}`. example: sim_card_01J8ZQ4T7K2M9X card_transaction_id: $ref: '#/components/schemas/KSUID' status: $ref: '#/components/schemas/SandboxCardSimulationStatus' ProblemDetails: type: object required: - type - title - status description: | Error response following RFC 9457 Problem Details. Public API error responses use this format. example: type: https://docs.dakota.xyz/api-reference/errors#not-found title: Customer Not Found status: 404 detail: Customer cst_2abc123 was not found in your organization. instance: https://api.platform.dakota.xyz/customers/cst_2abc123 request_id: req_7f3a8b2c properties: type: type: string format: uri description: | URI reference identifying the problem type. Resolves to human-readable documentation. example: https://docs.dakota.xyz/api-reference/errors#not-found title: type: string description: >- Short, human-readable summary of the problem type. Stable across occurrences. example: Customer Not Found status: type: integer description: HTTP status code for this occurrence. example: 404 detail: type: string description: Human-readable explanation specific to this occurrence. example: Customer cst_2abc123 was not found in your organization. instance: type: string format: uri description: The request path that triggered this error. example: https://api.platform.dakota.xyz/customers/cst_2abc123 request_id: type: string description: Unique request identifier. Include when contacting support. example: req_7f3a8b2c errors: type: array description: Field-level validation errors (present for validation failures). items: $ref: '#/components/schemas/ValidationError' resolution_url: type: string format: uri description: | A link the customer can follow to CLEAR this error, present only on problems with a concrete self-service remedy. Today this is returned by `#terms-not-accepted`, where it points at the hosted flow in which the outstanding agreement can be signed. The link is token-gated and usable as-is — send the customer to it directly rather than parsing it out of `detail`. example: >- https://onboarding.dakota.xyz/applications/2abc123?token=tok_7f3a8b2c user_message: type: string description: | A plain-language rendition of `detail` written for the end customer, present when one exists for this error. `detail` names request fields and actions so a machine caller (such as a payment agent drafting proposals) can self-correct; `user_message` says the same thing without API vocabulary. Clients that relay errors into a human surface (chat, email, UI) should show `user_message` when present and fall back to `detail`. example: >- ACH payments pay out USD, so a USDC payout isn't possible on this rail. Change the payout currency to USD and try again. KSUID: type: string title: KSUID description: >- KSUID is a 27-character globally unique ID that combines a timestamp with a random component. Used for all entity identifiers in the Dakota platform. pattern: ^[0-9A-Za-z]{27}$ minLength: 27 maxLength: 27 example: 1NFHrqBHb3cTfLVkFSGmHZqdDPi SandboxCardMerchant: type: object description: The merchant presenting a simulated card transaction. required: - descriptor properties: descriptor: type: string minLength: 1 maxLength: 40 description: Merchant name as it appears on the transaction. example: COFFEE ROASTERS mcc: type: string pattern: ^[0-9]{4}$ description: Merchant category code, four digits. example: '5814' acceptor_id: type: string maxLength: 32 description: Card acceptor identifier assigned by the acquirer. city: type: string maxLength: 32 description: Merchant city. example: BROOKLYN state: type: string maxLength: 32 description: Merchant state or region. example: NY country: type: string pattern: ^[A-Za-z]{3}$ description: ISO 3166-1 alpha-3 country code. example: USA SandboxCardSimulationStatus: type: string description: | Where a card simulation stands. `completed` means the card transaction exists and this response names it. `pending` means the simulation was accepted but the transaction has not been materialized yet; poll `GET /sandbox/simulations/{simulation_id}` for the identifier. `failed` means the simulation was not accepted: a refusal the endpoint could classify comes back as a problem response instead, so `failed` is what an unclassified one looks like. It can still name a card transaction, because the response reports whichever transaction the call resolved. A declined card authorization is not a failed simulation: the simulation succeeded and the decline arrives on the card transaction. enum: - pending - completed - failed ValidationError: type: object required: - field - message properties: field: type: string description: Field path using dot notation for nested fields. example: bank_account.routing_number message: type: string description: Human-readable description of the field error. example: Routing number must be exactly 9 digits code: type: string description: Machine-readable error code for this field. example: invalid_format securitySchemes: ApiKeyAuth: type: apiKey in: header name: x-api-key ````