> ## Documentation Index > Fetch the complete documentation index at: https://docs.beinfi.com/llms.txt > Use this file to discover all available pages before exploring further. # Read an invoice at checkout > Returns what the checkout page needs to show an invoice: your account's details, the invoice and the available payment methods. Takes no key; it runs in the payer's browser. ## OpenAPI ````yaml /api-reference/openapi.en.json get /pay/{slug}/invoices/{invoiceID} openapi: 3.1.0 info: title: Infi API version: 0.0.1 description: > The Infi REST API: catalog, customers, usage metering, subscriptions, invoices, payments and checkout. **Authentication.** Send your secret key as `Authorization: Bearer sk_test_…` (sandbox) or `sk_live_…` (production). The key prefix selects the environment. Checkout routes (`/pay/*`) and `/public/*` take no key: they run in the payer's browser. **Idempotency.** Every request that changes data requires an `Idempotency-Key` header. A retry with the same key returns the original response instead of running again. **Amounts.** Money and quantities travel as decimal strings (`"150.00"`, `"0.0001"`), never as floating-point numbers. **Errors.** The body carries `error_code` (stable, branch on it), `message` (for humans) and `tracer_id` (send it to support). Rate-limit and idempotency errors are nested under `error`, with `code` and `request_id`. servers: - url: https://api-sandbox.beinfi.com description: Sandbox - url: https://api.beinfi.com description: Production security: - bearerAuth: [] tags: - name: Catalog - name: Customers - name: Metering - name: Subscriptions - name: Invoices - name: Payments - name: Checkout - name: Coupons - name: Billing - name: Account - name: Webhooks - name: Test account - name: Rail - name: Storefronts paths: /pay/{slug}/invoices/{invoiceID}: get: tags: - Checkout summary: Read an invoice at checkout description: > Returns what the checkout page needs to show an invoice: your account's details, the invoice and the available payment methods. Takes no key; it runs in the payer's browser. operationId: getCheckoutSession parameters: - name: slug in: path required: true schema: type: string description: Your account's public identifier, as in checkout URLs. - name: invoiceID in: path required: true schema: type: string format: uuid description: Invoice ID. responses: '200': content: application/json: schema: $ref: '#/components/schemas/CheckoutSession' description: The invoice and payment options. '400': $ref: '#/components/responses/BadRequest' '404': $ref: '#/components/responses/NotFound' '429': $ref: '#/components/responses/RateLimited' security: [] components: schemas: CheckoutSession: type: object required: - merchant - invoice - testMode - paymentOptions - cardEnabled - cryptoEnabled properties: merchant: type: object required: - slug - name properties: slug: type: string name: type: string logoUrl: type: string format: uri description: Your account's name and look, as the payer sees them. invoice: $ref: '#/components/schemas/Invoice' testMode: type: boolean description: '`true` when the invoice is in sandbox: no real money moves.' paymentOptions: type: array items: $ref: '#/components/schemas/PublicPaymentOption' description: The payment methods available for this invoice. cardEnabled: type: boolean description: >- Whether card is available. Derived from `paymentOptions`; always present. cryptoEnabled: type: boolean description: Whether crypto payment is available on this checkout. paymentMethod: type: string enum: - pix - boleto - card - crypto description: >- Method of the confirmed payment. Present only once the invoice is paid. mandate: type: object required: - version - text properties: version: type: string text: type: string description: >- Authorization to save the card, which the payer must accept. Present only when card is available and the invoice is open. Send `version` as `consentTextVersion` when charging with `saveInstrument`. description: What the checkout page receives to show and charge an invoice. Invoice: type: object properties: id: type: string format: uuid customerId: type: - string - 'null' format: uuid description: >- The customer's product enrollment id. Set on product, usage and subscription invoices. payerId: type: - string - 'null' format: uuid description: The paying customer's id. Set on one-off invoices. subscriptionId: type: - string - 'null' format: uuid description: The subscription that generated the invoice invoiceNumber: type: - string - 'null' description: Sequential invoice number status: type: string enum: - draft - open - paid - void - uncollectible description: >- `draft` (being built), `open` (issued, awaiting payment), `paid`, `void` (canceled) or `uncollectible` (written off). currency: type: string description: Currency, as an ISO 4217 code (`BRL`). subtotal: type: string description: Sum of line items before tax and discounts. tax: type: string description: Tax on the invoice. total: type: string description: The invoice's final amount. amountDue: type: string description: How much is still owed. periodStart: type: - string - 'null' format: date-time description: Start of the billed period periodEnd: type: - string - 'null' format: date-time description: End of the billed period dueDate: type: - string - 'null' format: date-time description: Due date. finalizedAt: type: - string - 'null' format: date-time description: When the invoice was issued. paidAt: type: - string - 'null' format: date-time description: When the invoice was paid. successUrl: type: - string - 'null' description: Where checkout sends the buyer after payment. cancelUrl: type: - string - 'null' description: Where checkout sends the buyer if they back out. createdAt: type: string format: date-time lineItems: type: array items: $ref: '#/components/schemas/InvoiceLineItem' description: >- What a customer owes: line items, totals and status. Status: `draft` → `open` → `paid`, or `void` / `uncollectible`. PublicPaymentOption: oneOf: - $ref: '#/components/schemas/PublicPixPaymentOption' - $ref: '#/components/schemas/PublicCardPaymentOption' description: >- A payment method the checkout can offer. It is a hint: availability is checked again at charge time. Error: type: object required: - message - error_code - tracer_id properties: message: type: string description: Human-readable sentence. error_code: $ref: '#/components/schemas/ErrorCode' description: Stable error code. Branch on it. tracer_id: type: string description: Request id. Include it when contacting support. description: >- The standard error body. It is flat (no `error` wrapper) and the trace id is `tracer_id`. NotFoundError: type: object required: - message - error_code - tracer_id - resource properties: message: type: string error_code: $ref: '#/components/schemas/ErrorCode' tracer_id: type: string resource: type: string RequestError: type: object required: - error properties: error: type: object required: - code - message - request_id properties: code: $ref: '#/components/schemas/ErrorCode' message: type: string request_id: type: string InvoiceLineItem: type: object properties: id: type: string format: uuid type: type: string enum: - usage - recurring - proration - credit - adjustment - commitment - manual description: >- `usage` (metered usage), `recurring` (recurring fee), `proration` (pro-rata adjustment for a mid-period change), `credit`, `adjustment` (usage that arrived after its period was already invoiced), `commitment` (top-up to the minimum commitment) or `manual` (free-form line). meterId: type: - string - 'null' format: uuid description: The meter the usage came from priceId: type: - string - 'null' format: uuid description: The price applied to this line. description: type: string quantity: type: string description: Quantity billed unitPrice: type: - string - 'null' description: Price per unit amount: type: string description: Line total proration: type: boolean description: '`true` when the line is a pro-rated amount.' description: One line on an invoice. PublicPixPaymentOption: type: object additionalProperties: false required: - method - flow properties: method: type: string const: pix flow: type: string const: pix description: How the payment is completed in the browser. PublicCardPaymentOption: type: object additionalProperties: false required: - method - provider - flow - supportsSavedInstrument properties: method: type: string const: card provider: type: string enum: - adyen - stripe flow: type: string enum: - adyen_session - stripe_payment_intent description: How the payment is completed in the browser. supportsSavedInstrument: type: boolean description: Whether the payer can save the card for future charges. ErrorCode: type: string examples: - internal_error - validation_failed - bad_request - unauthorized - forbidden - not_found - conflict - rate_limited description: >- Stable error code. The list is open: besides the generic codes, each area defines its own (`coupon_expired`, `insufficient_balance`, `version_not_draft`, `idempotency_key_reused`…). Handle a code you do not recognize by its HTTP status and show `message`; do not fail parsing the response. responses: BadRequest: content: application/json: schema: $ref: '#/components/schemas/Error' description: Malformed request. NotFound: content: application/json: schema: $ref: '#/components/schemas/NotFoundError' description: Resource not found. RateLimited: headers: Retry-After: schema: type: integer content: application/json: schema: $ref: '#/components/schemas/RequestError' description: Rate limit exceeded. `Retry-After` gives the wait in seconds. securitySchemes: bearerAuth: type: http scheme: bearer description: >- Your account's secret key: `Authorization: Bearer sk_test_…` or `sk_live_…`. Server-side only. ````