# NS App — Documentation

Reference documentation for the **NS App** ERPNext/Frappe custom application
(NS Innovations). This app extends the Sales workflow with embedded card
payments, AutoPay vaulting, multi-invoice settlement, guided customer
onboarding, and branded print formats.

## Contents

| Document | What's in it |
|----------|--------------|
| [ARCHITECTURE.md](./ARCHITECTURE.md) | What the app does, component map, payment flow diagram, data model, external dependencies, configuration, and known tech debt. |
| [DESIGN_SPEC.md](./DESIGN_SPEC.md) | Goals/non-goals, personas, functional requirements, server API contracts, design constraints, failure modes, and acceptance criteria. |
| [SECURITY_NOTES.md](./SECURITY_NOTES.md) | Current security posture and a prioritized hardening list. |

## Quick orientation

- **Backend:** `ns_app/api/payments.py` (NMI gateway), `ns_app/api/customer.py`
  (atomic customer creation).
- **Frontend:** `ns_app/public/js/sales_invoice.js` (payment UI),
  `ns_app/public/js/customer_quick_entry.js` (customer quick entry).
- **Wiring:** `ns_app/hooks.py`.
- **Print formats:** `ns_app/print_formats/` (shipped as fixtures).

## Related

- Root [README.md](../README.md) — install & configuration guide.
- `ns_app/api/payment_flow_documentation.md` — original narrative walkthrough of
  the payment flow (kept for historical context; superseded by
  [ARCHITECTURE.md](./ARCHITECTURE.md) §3).