---
title: "Get Invoice"
method: GET
path: "/api/v1/payments/{project_id}/invoice"
tags: ["payments"]
---

# Get Invoice

`GET /api/v1/payments/{project_id}/invoice`

Get the invoice for a completed payment.

## Path parameters

- `project_id` string, uuid, required

## Response `200`

Successful Response

- InvoiceResponse — Invoice summary returned in payment detail views. ``invoice_number`` is the sequential accounting identifier (``INV-YYYY-NNNNN``) and stays stable in the DB for accounting reconciliation. ``display_number`` is the project-derived short form (``INV-{project_id_first8}``) shown in the UI and on PDFs so quote + invoice + project share a visually-consistent identifier. Backend resolves ``display_number`` at response build time — frontends should prefer it for display and only surface ``invoice_number`` if accounting context is needed.
  - `id` string, uuid, required
  - `payment_id` string, uuid, required
  - `project_id` string, uuid, required
  - `invoice_number` string, required
  - `display_number` string, nullable
  - `status` string, required
  - `amount` string, required
  - `subtotal` string, nullable
  - `tax_amount` string, nullable
  - `tax_rate` string, nullable
  - `tax_excluded` boolean
  - `additional_line_items_post_tax` AdditionalLineItemOutput[], nullable
    - `label` string, required
    - `quantity` integer, nullable — Optional display quantity for admin-entered misc line items. When set, the PDF shows the quantity alongside the label. The amount remains the line amount, not a unit price.
    - `amount` string, required
  - `currency` string, required
  - `issued_at` string, date-time, nullable
  - `paid_at` string, date-time, nullable
  - `invoice_pdf_url` string, nullable
  - `pdf_generated_at` string, date-time, nullable
  - `notes` string, nullable
  - `created_at` string, date-time, required
  - `updated_at` string, date-time, required

## Other responses

- `422` — Validation Error

---

[API](https://skmtc.dev/prototyping/apis/prototyping-io-api.md) · [All operations](https://skmtc.dev/prototyping/apis/prototyping-io-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/prototyping/prototyping-io-api/revisions/f4a0079fbb57/schema)