Perfect 🚀 this is the last step — let’s add the docs so your app is release-ready.

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✅ Step 7 → Documentation

We’ll add two files:

1. README.md → end-user guide (for your customers / ERPNext admins).
2. README_DEV.md → developer guide (for you / contributors).

---

1. README.md

Path:

nextpos_printing/README.md

# NextPOS Printing

**NextPOS Printing** is a Frappe app that connects ERPNext POS to QZ Tray for reliable **thermal receipt printing** and **cash drawer handling**.

---

## Features
- 🔌 QZ Tray integration (secure printing via certificates/keys).
- 🖨️ Automatic receipt printing after invoice submit.
- ✂️ Cut modes (full, partial, or none).
- 💵 Open cash drawer automatically or manually.
- 📋 POS sidebar with quick buttons:
  - Print Current
  - Reprint Last
  - Open Drawer
- ⚙️ Settings panel with:
  - Default printer
  - Auto-print toggle
  - Copies, cut mode, feed lines
  - Custom header/footer text
  - Test Print and Test Drawer buttons
  - Setup Wizard (one-click defaults)

---

## Requirements
- ERPNext v15
- QZ Tray installed and running → [Download QZ Tray](https://qz.io/download/)
- Site config with QZ keys:
  ```json
  {
    "npp_cert_pem": "base64-encoded certificate",
    "npp_private_key": "base64-encoded private key"
  }

---

Installation

From your bench folder:

bench get-app git@bitbucket.org:opennodescanada/nextpos_printing.git
bench --site yoursite install-app nextpos_printing
bench build
bench clear-cache
bench restart

---

Usage

1. Go to NextPOS Settings in ERPNext.
2. Run Setup Wizard to apply defaults.
3. Use Test Print and Test Drawer to verify connection.
4. Open POS and use the sidebar buttons, or let receipts auto-print.

---

Support

Developed by Open Node Solutions Email: support@opennodes.ca

---

### 2. `README_DEV.md`

Path:  

nextpos_printing/README_DEV.md

```markdown
# NextPOS Printing – Developer Notes

## Folder Structure

nextpos_printing/ ├── nextpos_printing/ │ ├── api/ # Whitelisted backend endpoints │ │ ├── init.py │ │ ├── print.py # Print payloads for QZ │ │ └── qz.py # Certificate + signing for QZ Tray │ ├── printing/ # Receipt renderers │ │ ├── init.py │ │ ├── receipt.py # ESC/POS renderer │ │ └── templates/ │ │ └── receipt.jinja # Fallback receipt template │ ├── utils/ │ │ ├── init.py │ │ └── settings.py # Fetch settings and printer mappings │ ├── nextpos_printing/ # DocTypes │ │ └── doctype/ │ │ ├── nextpos_printer_mapping/ │ │ └── nextpos_settings/ │ ├── public/ │ │ ├── css/ │ │ │ └── nextpos_printing_custom.css │ │ └── js/ │ │ ├── nextpos_pos.js │ │ └── qz-tray.js │ ├── hooks.py │ └── ...

---

## Key Files

- **hooks.py** → injects `nextpos_pos.js` into POS, loads CSS.  
- **nextpos_pos.js** → main frontend logic:
  - Connects to QZ
  - Print invoices
  - Open drawer
  - Adds POS sidebar buttons
  - Replaces ERPNext print button
  - Auto-print invoices  
- **nextpos_settings.js** → UI logic for Test Print, Test Drawer, Setup Wizard.  
- **receipt.py** → ESC/POS rendering logic.  
- **settings.py** → mapping POS Profile → printer config.  

---

## Development Commands

```bash
# Build assets
bench build

# Apply schema updates
bench --site <site> migrate

# Clear cache
bench clear-cache

# Restart processes
bench restart

---

Release Checklist

• Verify Test Print and Test Drawer work in Settings.

• Verify auto-print after invoice submit.

• Verify sidebar buttons (Print Current, Reprint Last, Drawer).

• Run bench build && bench clear-cache && bench restart.

• Tag stable release in git:

  git tag -a v1.0.0 -m "Stable release"
  git push origin v1.0.0

---

Notes

• CSS must remain global (.npp-sidebar, .npp-btn) with position: fixed.
• Do not scope styles under .point-of-sale-app → it breaks layout.