# `POST /api/print/invoice` > **Endpoint:** `POST /api/print/invoice` > **Auth Scope:** Profile Protected (`verify_operational_profile_access`) > **Target Service:** Local DaemonX Bridge Daemon (`127.0.0.1:9123`) > **Introduced In:** v1.0.0 > **Last Updated:** v1.0.0 > **Rendering Engine:** Headless Microsoft Edge / Google Chrome (300 DPI) --- ## 1. Description & Purpose `POST /api/print/invoice` enables web applications to print rich, fully styled HTML documents directly to any physical Windows printer (inkjet, laser, or high-resolution continuous thermal rolls) **without displaying the browser print dialog (`Ctrl+P`)**. ### How It Works Under the Hood: 1. **HTML Ingestion**: Accepts a complete HTML string with embedded CSS (fonts, Flexbox/Grid, SVG logos, barcodes, tables). 2. **Sandbox Watermark Injection**: If the counter is running in a Sandbox environment, DaemonX injects top/bottom security banners and a 45° diagonal watermark before rendering. 3. **Headless Vector Rasterization**: Microsoft Edge or Google Chrome renders the HTML headlessly into an exact vector PDF at 300 DPI. 4. **Direct Spooler Dispatch**: The generated vector document is dispatched directly to the target Windows printer queue via `System.Drawing.Printing.PrintDocument`. 5. **Instant Cleanup**: All temporary PDF and image artifacts are immediately unlinked from `%TEMP%`. --- ## 2. Authentication & Required Headers | Header Name | Type | Required | Description | Example | | :--- | :--- | :--- | :--- | :--- | | `Content-Type` | `string` | **Yes** | `application/json` | `application/json` | | `Origin` | `string` | **Yes** | Web POS browser origin. Must be whitelisted in profile. | `https://pos.yourdomain.com` | | `X-Bridge-Counter-Id` | `string` (UUID) | **Yes** | Target counter UUID registered on this workstation. | `d402ddec-ecf7-4b39-b57a-86ce6008df05` | | `X-Bridge-Profile-Secret` | `string` | **Yes** | Counter secret issued during pairing (`dxp_...`). | `dxp_202b541b2a72ecc32867e0f62b26b...` | --- ## 3. TypeScript Contracts ```typescript export interface InvoicePrintRequest { /** Target Windows printer name (from GET /api/printers) */ printer_name: string; /** Full standalone HTML document string with
STUDIO MILAN
Commercial Tax Invoice #INV-8891
DescriptionQtyUnit PriceTotal
Italian Linen Blazer (Navy - 40R)1LKR 28,500.00LKR 28,500.00
Custom Tailoring & Alteration1LKR 3,500.00LKR 3,500.00
GRAND TOTALLKR 32,000.00
" } ``` #### Successful Response (200 OK) ```json { "success": true, "counter_id": "d402ddec-ecf7-4b39-b57a-86ce6008df05", "printer": "EPSON L130 Series", "format": "A4", "pages": 1, "copies": 1 } ``` --- ### Example B: Offline Allowance Lockout (403 Forbidden) ```json { "detail": { "error": "DAEMONX_OFFLINE_ALLOWANCE_EXHAUSTED", "message": "Emergency offline allowance exhausted. Reconnect this counter to continue.", "counter_id": "d402ddec-ecf7-4b39-b57a-86ce6008df05", "offline_remaining": 0, "reconnect_required": true, "gate_reason": "OFFLINE_ALLOWANCE_EXHAUSTED", "operation": "print_invoice" } } ``` --- ## 6. HTML Rendering Best Practices for Silent Spooling To ensure pixel-perfect printing across all printer brands: 1. **Use Self-Contained Styles**: Do not rely on external CSS stylesheets (``) that require internet requests during rendering. Inline your CSS rules in a `