> ## Documentation Index > Fetch the complete documentation index at: https://docs.qonto.com/llms.txt > Use this file to discover all available pages before exploring further. # Invoices and billing > Client invoices, supplier invoices, quotes, credit notes, and products The billing surface covers every document you exchange with your customers and suppliers, plus the reusable product catalog that backs them. ## Client invoices | Tool | What it does | Upstream | | ------------------------------ | ---------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `list_client_invoices` | Paginated list of issued invoices. Status filter: `draft` / `unpaid` / `paid` / `canceled`. | [List client invoices](/api-reference/business-api/expense-management/client-quotes-notes/client-invoices/list-client-invoices) | | `get_client_invoice` | Fetch one invoice with the heavier fields the list view drops (regulatory blocks, e-invoicing lifecycle events). | [Retrieve a client invoice](/api-reference/business-api/expense-management/client-quotes-notes/client-invoices/retrieve-a-client-invoice) | | `create_client_invoice` | Create an invoice. `client_id` must exist with a currency; `payment_methods.iban` must belong to a Qonto account on the organization. Default status is `draft`. | [Create a client invoice](/api-reference/business-api/expense-management/client-quotes-notes/client-invoices/create-a-client-invoice) | | `update_client_invoice` | Patch a draft. Finalized, canceled, or paid invoices reject updates. | [Update a client invoice](/api-reference/business-api/expense-management/client-quotes-notes/client-invoices/update-a-client-invoice) | | `delete_client_invoice` | Delete a draft. Only `draft` accepted; cancel finalised invoices through `change_client_invoice_status`. | [Delete a client invoice](/api-reference/business-api/expense-management/client-quotes-notes/client-invoices/delete-a-client-invoice) | | `change_client_invoice_status` | Composite lifecycle transition: `finalize` (draft to unpaid, locks against update and delete) or `cancel` (unpaid to canceled, irreversible). | [Finalize](/api-reference/business-api/expense-management/client-quotes-notes/client-invoices/finalize-a-client-invoice) / [Cancel](/api-reference/business-api/expense-management/client-quotes-notes/client-invoices/mark-a-client-invoice-as-canceled) | | `mark_client_invoice_as_paid` | Move `unpaid` to `paid` and stamp `paid_at` (defaults to today). Idempotent on already-paid invoices, updates the date. | [Mark as paid](/api-reference/business-api/expense-management/client-quotes-notes/client-invoices/mark-a-client-invoice-as-paid) | | `send_client_invoice` | Email an invoice to one or more recipients. The invoice status is unchanged. | [Send a client invoice](/api-reference/business-api/expense-management/client-quotes-notes/client-invoices/send-a-client-invoice) | **Try it** > Draft a €1,200 + 20% VAT invoice to ACME for "Consulting June 2026", finalize it, and email it to [billing@acme.com](mailto:billing@acme.com). > > Mark the latest unpaid invoice from ACME as paid on 2026-05-15. ## Credit notes | Tool | What it does | Upstream | | -------------------- | --------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------- | | `list_credit_notes` | List credit notes (partial- or full-refund counter-documents linked to client invoices). | [List credit notes](/api-reference/business-api/expense-management/client-quotes-notes/credit-notes/list-credit-notes) | | `get_credit_note` | Fetch one credit note with all fields. | [Retrieve a credit note](/api-reference/business-api/expense-management/client-quotes-notes/credit-notes/retrieve-a-credit-note) | | `create_credit_note` | Create a credit note tied to an existing invoice. Currency must match the invoice; cumulative total cannot exceed it. | [Create a credit note](/api-reference/business-api/expense-management/client-quotes-notes/credit-notes/create-a-credit-note) | **Try it** > Issue a €120 credit note against invoice INV-2026-042. ## Quotes | Tool | What it does | Upstream | | -------------- | -------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------- | | `list_quotes` | List client quotes (commercial offers issued before invoicing). | [List quotes](/api-reference/business-api/expense-management/client-quotes-notes/quotes/list-quotes) | | `get_quote` | Fetch one quote with the public `quote_url`. | [Retrieve a quote](/api-reference/business-api/expense-management/client-quotes-notes/quotes/retrieve-a-quote) | | `create_quote` | Create a quote (initial status `pending_approval`). Items with `vat_rate=0` need a `vat_exemption_code`. | [Create a quote](/api-reference/business-api/expense-management/client-quotes-notes/quotes/create-a-quote) | | `update_quote` | Patch one quote by UUID. | [Patch a quote](/api-reference/business-api/expense-management/client-quotes-notes/quotes/patch-a-quote) | | `delete_quote` | Permanently delete a quote. | [Delete a quote](/api-reference/business-api/expense-management/client-quotes-notes/quotes/delete-a-quote) | | `send_quote` | Email a quote to one or more recipients. | [Send a quote](/api-reference/business-api/expense-management/client-quotes-notes/quotes/send-a-quote) | **Try it** > Send the latest draft quote for ACME to [ops@acme.com](mailto:ops@acme.com). ## Supplier invoices | Tool | What it does | Upstream | | -------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------ | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `list_supplier_invoices` | Paginated list of supplier invoices. Filter client-side on `status` (server-side filter not yet exposed). | [List supplier invoices](/api-reference/business-api/expense-management/supplier-invoices/list-supplier-invoices) | | `get_supplier_invoice` | Fetch one supplier invoice (status, supplier, dates, amounts, taxes, IBAN, matched\_transactions, approval\_workflow, available\_actions). | [Retrieve a supplier invoice](/api-reference/business-api/expense-management/supplier-invoices/retrieve-a-supplier-invoice) | | `change_supplier_invoice_status` | Composite lifecycle transition: `reject` (irreversible) or `mark_as_paid` / `unmark_as_paid`. | [Reject](/api-reference/business-api/expense-management/supplier-invoices/reject-supplier-invoice) / [Mark as paid](/api-reference/business-api/expense-management/supplier-invoices/mark-supplier-invoice-as-paid) / [Unmark as paid](/api-reference/business-api/expense-management/supplier-invoices/unmark-supplier-invoice-as-paid) | **Try it** > Mark supplier invoice INV-3382 as paid on 2026-05-20. > > Which supplier invoices are still unpaid after 60 days? ## Products The product catalog backs every line item on a client invoice, quote, or credit note. | Tool | What it does | Upstream | | ---------------- | ------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------- | | `list_products` | List the reusable catalog of goods and services. Use a product id as a line item on invoices, quotes, or credit notes. | [List products](/api-reference/business-api/expense-management/products/list-products) | | `create_product` | Create a product. Required: `title` (max 120 chars), `type` (`good` or `service`), `unit_price` (value + currency), `vat_rate`. | [Create a product](/api-reference/business-api/expense-management/products/create-a-product) | **Try it** > Add a "Consulting hour" service product at €150 + 20% VAT.