> ## Documentation Index > Fetch the complete documentation index at: https://alguna.com/docs/llms.txt > Use this file to discover all available pages before exploring further. # Apply a credit note > Applies a draft credit note. Applying to a paid invoice can optionally trigger a refund to the original payment method or a wallet. Applying to an Alguna-managed invoice in `issued` or `overdue` records a pre-payment credit without issuing a refund. Once applied, the credit note cannot be modified. ## OpenAPI ````yaml /api-reference/v2/specs/2026-04-01.json post /credit-notes/{id}/apply openapi: 3.1.0 info: title: Alguna Public API version: '2026-04-01' servers: - url: https://api.alguna.io security: - bearerAuth: [] tags: - name: Billing Events and Metrics - name: Credit Notes - name: Credits - name: Customer Portal Sessions - name: Customers - name: Insights - name: Invoices - name: Payments - name: Plans - name: Product Bundles - name: Products - name: Refunds - name: Revenue Schedules - name: Subscription Changes - name: Subscription Versions - name: Subscriptions - name: Wallet Grants - name: Wallets paths: /credit-notes/{id}/apply: post: tags: - Credit Notes summary: Apply a credit note description: >- Applies a draft credit note. Applying to a paid invoice can optionally trigger a refund to the original payment method or a wallet. Applying to an Alguna-managed invoice in `issued` or `overdue` records a pre-payment credit without issuing a refund. Once applied, the credit note cannot be modified. operationId: apply-credit-note parameters: - in: header name: Alguna-Version required: true schema: enum: - '2026-04-01' type: string - in: header name: Idempotency-Key schema: description: >- A unique string used to ensure the request is processed exactly once. If you retry a request with the same idempotency key within 24 hours, the original response is returned without re-executing the operation. example: ik_a1b2c3d4e5f6 maxLength: 255 type: string - in: path name: id required: true schema: description: Unique identifier for the credit-note type: string requestBody: content: application/json: schema: $ref: '#/components/schemas/ApplyCreditNoteRequest' required: true responses: '200': content: application/json: schema: $ref: '#/components/schemas/CreditNoteResponse' description: Success headers: Idempotency-Key: description: Echo of the idempotency key provided in the request schema: type: string Idempotent-Replayed: description: >- Whether this response was replayed from a previous request (true) or freshly executed (false) schema: type: boolean '400': content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' description: Bad Request '401': content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' description: Unauthorized '404': content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' description: Not Found '409': content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' description: >- Conflict — a request with this idempotency key is currently being processed '422': content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' description: Unprocessable Entity '500': content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' description: Internal Server Error components: schemas: ApplyCreditNoteRequest: properties: do_refund: description: Whether to issue a refund when applying to a paid invoice example: false type: boolean refund_destination: description: Where to send the refund when refunding a paid invoice enum: - original_payment - wallet example: original_payment nullable: true type: string wallet_id: description: >- Wallet to refund to when refund_destination is wallet for a paid-invoice refund example: wlt_01H1VECT nullable: true type: string required: - do_refund type: object CreditNoteResponse: properties: accounting_credit_note_id: description: Credit note ID in the accounting system nullable: true type: string accounting_credit_note_url: description: URL to the credit note in the accounting system nullable: true type: string accounting_integration_id: description: Accounting integration ID nullable: true type: string accounting_provider: description: Accounting provider name nullable: true type: string apply_date: description: Date the credit note was applied example: '2026-03-01T00:00:00Z' format: date-time nullable: true type: string attachments: description: Attachments on this credit note items: $ref: '#/components/schemas/CreditNoteAttachmentResponse' type: array billing_period_end: description: End of the billing period example: '2026-01-31T23:59:59Z' format: date-time nullable: true type: string billing_period_start: description: Start of the billing period example: '2026-01-01T00:00:00Z' format: date-time nullable: true type: string created_at: description: Timestamp when the credit note was created example: '2026-04-01T10:00:00Z' format: date-time type: string credit_date: description: Date of the credit example: '2026-03-01T00:00:00Z' format: date-time nullable: true type: string currency: description: Currency code example: USD type: string customer_id: description: Customer this credit note belongs to example: cust_01H1VECT type: string description: description: Description of the credit note example: Overcharge credit type: string external_reference: description: External reference identifier type: string id: description: Unique identifier for the credit note example: cn_01H1VECT type: string invoice_id: description: Associated invoice ID nullable: true type: string is_pdf_available: description: Whether a PDF is available for download type: boolean last_refund_date: description: Date of the last refund format: date-time nullable: true type: string last_refund_id: description: ID of the last refund nullable: true type: string legal_entity_id: description: Legal entity ID nullable: true type: string line_items: description: Line items on this credit note items: $ref: '#/components/schemas/CreditNoteLineItemResponse' type: array purchase_order_number: description: Purchase order number nullable: true type: string status: description: Current status of the credit note enum: - draft - applied - void - pending_refund example: draft type: string subtotal: description: Subtotal before tax example: '100.00' type: string sync_enabled: description: Whether accounting sync is enabled type: boolean tax: description: Tax amount example: '10.00' type: string total: description: Total amount including tax example: '110.00' type: string updated_at: description: Timestamp when the credit note was last updated example: '2026-04-01T12:30:00Z' format: date-time type: string void_date: description: Date the credit note was voided format: date-time nullable: true type: string required: - attachments - created_at - currency - customer_id - description - external_reference - id - is_pdf_available - line_items - status - subtotal - sync_enabled - tax - total - updated_at type: object ErrorResponse: properties: detail: type: string status: format: int64 type: integer required: - status - detail type: object CreditNoteAttachmentResponse: properties: file_url: description: URL to the attachment file type: string title: description: Title of the attachment example: Credit Note PDF type: string required: - file_url - title type: object CreditNoteLineItemResponse: properties: additional_description: description: Additional description for the line item nullable: true type: string billing_period_end: description: End of the billing period example: '2026-01-31T23:59:59Z' format: date-time type: string billing_period_start: description: Start of the billing period example: '2026-01-01T00:00:00Z' format: date-time type: string description: description: Description of the line item example: Platform usage credit type: string id: description: Unique identifier for the line item example: cnli_01H1VECT type: string invoice_line_item_id: description: Associated invoice line item ID nullable: true type: string is_editable: description: Whether the line item can be edited type: boolean product_id: description: Associated product ID example: prod_01H1VECT nullable: true type: string quantity: description: Quantity of items example: '1' type: string tax_amount: description: Tax amount for the line item example: '10.00' nullable: true type: string tax_rate: description: Tax rate applied to the line item example: '0.10' nullable: true type: string total_price: description: Total price of the line item example: '100.00' type: string unit_price: description: Unit price of the line item example: '100.00' type: string required: - billing_period_end - billing_period_start - description - id - is_editable - quantity - total_price - unit_price type: object securitySchemes: bearerAuth: bearerFormat: API Key description: API key authentication. Pass your API key as a Bearer token. scheme: bearer type: http ````