> ## Documentation Index > Fetch the complete documentation index at: https://docs.boomfi.xyz/llms.txt > Use this file to discover all available pages before exploring further. # Create Subscription Invoice > Create an invoice for a subscription, or return the existing invoice with the same due date. ## OpenAPI ````yaml /openapi.yaml post /subscriptions/{subscriptionID}/invoices openapi: 3.1.0 info: contact: email: support@boomfi.xyz name: API Support description: >- The BoomFi Merchants API provides a set of endpoints for merchants to manage their accounts, transactions, and more. Hosts differ per brand/environment; use the brand-specific base URL from the docs. title: BoomFi Merchants API version: '1.0' servers: - url: https://mapi.boomfi.xyz/v1 description: Production - url: https://mapi-test.boomfi.xyz/v1 description: Test security: [] tags: - description: Payment links name: Paylinks - description: Billing plans name: Plans - description: Subscriptions name: Subscriptions - description: Customer records name: Customers - description: Invoices name: Invoices - description: Payments name: Payments - description: Organisation events name: Events - description: Organisation profile and display settings name: Organisation - description: Webhook and request-signing secrets name: Secrets - description: Settlement accounts name: Accounts - name: External Accounts - description: Managed virtual accounts, balances, pay-in, and payout name: Virtual Accounts - description: Partner-managed accounts, virtual accounts, pay-in, and payout name: Partners - description: Partner maintain-balance automations name: Partner Balance Monitoring - name: Checkout Sessions paths: /subscriptions/{subscriptionID}/invoices: post: tags: - Subscriptions summary: Create Subscription Invoice description: >- Create an invoice for a subscription, or return the existing invoice with the same due date. parameters: - description: Unique subscription identifier (sub_... or raw UUID) in: path name: subscriptionID required: true schema: type: string requestBody: content: application/json: schema: $ref: '#/components/schemas/subscriptions.CreateSubscriptionInvoice' description: Invoice request required: true responses: '200': description: OK content: application/json: schema: $ref: '#/components/schemas/internal.Response-models_Invoice' '400': description: Bad Request content: application/json: schema: $ref: '#/components/schemas/internal.ErrorResponse' '404': description: Not Found content: application/json: schema: $ref: '#/components/schemas/internal.ErrorResponse' '500': description: Internal Server Error content: application/json: schema: $ref: '#/components/schemas/internal.ErrorResponse' security: - ApiKeyAuth: [] components: schemas: subscriptions.CreateSubscriptionInvoice: properties: due_date: description: Invoice due date (RFC3339). type: string properties: additionalProperties: {} description: Additional properties as a key-value map. type: object title: description: Invoice title or subject line. type: string type: object internal.Response-models_Invoice: properties: data: allOf: - $ref: '#/components/schemas/models.Invoice' description: Response payload when the request succeeded. error: description: True when the request failed. type: boolean message: description: Human-readable status or error message. type: string type: object internal.ErrorResponse: properties: error: allOf: - $ref: '#/components/schemas/internal.ErrorStruct' description: Error details including HTTP-style code and message. type: object models.Invoice: properties: amount: description: amount type: string created_at: description: created_at type: string currency: description: currency type: string customer_id: description: customer_id type: string due_at: description: due_at type: string dunning_status: allOf: - $ref: '#/components/schemas/docenums.DunningStatus' description: dunning_status id: description: id type: string issuing_at: description: issuing_at type: string org_id: description: org_id type: string payment_status: allOf: - $ref: '#/components/schemas/docenums.PaymentStatus' description: payment_status properties: description: properties items: type: integer type: array reference: description: reference type: string source: allOf: - $ref: '#/components/schemas/docenums.BillingSource' description: source status: allOf: - $ref: '#/components/schemas/docenums.InvoiceStatus' description: status updated_at: description: updated_at type: string type: object internal.ErrorStruct: properties: code: description: |- Error code Example: 400 example: 400 type: integer errors: description: List of errors items: $ref: '#/components/schemas/internal.SingleError' type: array message: description: |- Error message Example: Insufficient quantity example: Insufficient quantity type: string type: object docenums.DunningStatus: enum: - Unknown - InProgress - Exhausted - Stopped - Succeeded type: string x-enum-varnames: - DunningStatusUnknown - DunningStatusInProgress - DunningStatusExhausted - DunningStatusStopped - DunningStatusSucceeded docenums.PaymentStatus: enum: - Unknown - RequiresPaymentMethod - RequiresConfirmation - RequiresAction - Processing - Succeeded - Canceled - Failed type: string x-enum-varnames: - PaymentStatusUnknown - PaymentStatusRequiresPaymentMethod - PaymentStatusRequiresConfirmation - PaymentStatusRequiresAction - PaymentStatusProcessing - PaymentStatusSucceeded - PaymentStatusCanceled - PaymentStatusFailed docenums.BillingSource: enum: - Lago - BoomFi - Stripe - Chargebee - QuickBooks type: string x-enum-varnames: - BillingSourceLago - BillingSourceBoomFi - BillingSourceStripe - BillingSourceChargebee - BillingSourceQuickBooks docenums.InvoiceStatus: enum: - Unknown - Draft - Open - Paid - Void - Uncollectible type: string x-enum-varnames: - InvoiceStatusUnknown - InvoiceStatusDraft - InvoiceStatusOpen - InvoiceStatusPaid - InvoiceStatusVoid - InvoiceStatusUncollectible internal.SingleError: properties: domain: description: |- Domain Example: orders example: orders type: string reason: description: |- Error Reason Example: InsufficientQuantity example: InsufficientQuantity type: string type: object securitySchemes: ApiKeyAuth: in: header name: X-API-KEY type: apiKey ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.