System Manual & Architecture Guide

Offline-First SQLite Architecture

In high-volume food service, cloud network latency and internet dropouts can halt front-of-house operations. RestroMithra employs a hybrid edge-cloud architecture:

When WAN connectivity cuts out:

• Cashiers continue billing, accepting cash/card payments, and generating physical printouts without interruption.
• Station printers continue receiving KOT dispatch instructions via local LAN broadcasting.
• When broadband or 4G restores, an automatic background queue worker drains and syncs all transactions to the cloud PostgreSQL database with strict idempotency keys to prevent duplicate entries.

POS Cashier Terminal & Table Grid

The POS terminal interface is optimized for rapid keystrokes and single-finger touchscreen taps.

Floor Map States

Dining tables display color-coded status badges:

• Green (Vacant): Ready for seating and new order placement.
• Amber (Occupied / In Kitchen): Running KOTs placed; meals being cooked.
• Blue (Billed): Final bill generated; awaiting payment confirmation.
• Grey (Cleaning): Table being bussed for next guest.

Split Billing Protocol

Cashiers can split any active table by seat number, item selection, or equal monetary fractions. Each split invoice receives its own sequential GST tax invoice number.

Station-Based KOT Routing & Kitchen Displays (KDS)

RestroMithra routes each dish on a single order to its appropriate cooking station:

Recipe Margin Costing & Bill of Materials (BOM)

Accurate food costing protects restaurant profit margins. In RestroMithra, each menu item is defined with its exact raw ingredient yields:

Menu Item: Chicken Biryani (Single Portion)
Bill of Materials (BOM):
├── Basmati Rice: 150 grams
├── Chicken Breast / Bone-in: 200 grams
├── Biryani Gravy Base: 80 ml
├── Pure Ghee: 20 grams
├── Fried Onion (Birista): 15 grams
└── Whole Spices Blend: 5 grams

When a bill is marked settled, these precise raw quantities are instantly deducted from your central pantry inventory. If stocks drop below safety thresholds, automatic reorder notices are dispatched to your procurement manager.

Indian GST Tax Invoicing Rules

RestroMithra is pre-configured with the latest Central Board of Indirect Taxes and Customs (CBIC) rules for Indian restaurants:

• 5% Standard Restaurant GST: 2.5% CGST + 2.5% SGST without Input Tax Credit (ITC), applicable for standalone restaurants, cafes, QSRs, and cloud kitchens.
• 18% Full Rate GST: 9% CGST + 9% SGST with ITC, applicable for restaurants located in hotels with room tariffs exceeding ₹7,500/night or outdoor catering contracts.
• 1% Composition Scheme: 0.5% CGST + 0.5% SGST for eligible small food businesses under section 10 of the CGST Act.
• E-Invoice & HSN/SAC Classification: Automatic assignment of SAC code 996331 (Restaurant services) or 996332 (Takeaway / delivery food services).

Thermal Receipt Printers & Hardware Setup

RestroMithra communicates with receipt printers using standard ESC/POS protocol instructions. Supported configurations:

• USB Direct Connect: Plug Epson TM-T82 or TVS RP3200 directly into cashier PC. Detected automatically via the local agent.
• Ethernet LAN Kitchen Printers: Connect kitchen printers via CAT6 ethernet cable to your local Wi-Fi router. Assign static IP (e.g. 192.168.1.200) for multi-station ticket firing.
• Bluetooth Mobile Printers: Pair 2-inch (58mm) battery-powered thermal printers for food trucks and pop-up counters.
• RJ11 Cash Drawer: Automatic kick-pulse triggers drawer drawer open on cash tender confirmation.

Dynamic QR Code Dine-In Ordering

Enable contactless ordering directly at guest tables without requiring app downloads. Each table possesses a cryptographic QR URL (e.g., /qr/branch-id/table-id). Guests scan, browse allergen-tagged digital menus, select items, and send orders straight to the kitchen KDS screen.