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CASE STUDYE-COMMERCE · IOT VENDING PLATFORM

StackD

An IoT-connected smart vending platform with cashless payments, corporate wallets, warehouse-to-machine inventory, a promotions engine and bidirectional Zoho ERP sync.

44Weeks operated
2k+Hours of work
10Engineers

The brief

Build and extend a smart vending platform (StackD) that enables cashless vending transactions via multiple payment modes, connects physical vending machines to a backend via IoT, and provides operational tooling for admins, refill teams, and corporate clients — with a focus on launching the corporate wallet feature, stabilizing production, and integrating Zoho ERP.

What we built

A full-stack smart vending platform spanning 4 frontend surfaces (PWA, React backoffice, TouchScreen kiosk app, Android M2 Refill app) and a Node.js backend with IoT (MQTT) machine communication. Core capabilities include: multi-mode cashless payments (QR static/dynamic via PayU & Paytm, RFID, UPI, wallet), a corporate wallet system with RBAC, cron-based auto-refill, spending limits, and company wallet rails, warehouse-to-machine inventory management with batch/expiry tracking, a promotions engine (BOGO, combo, percentage, flat discounts), Zoho Books/Inventory ERP bidirectional sync with GST compliance, multi-tenant RBAC for super-admin/admin/client/refill-team/end-user, real-time reporting dashboards with read replica optimization, and a tuck-shop retail sub-module. Both iOS (App Store) and Android (Play Store) native apps were deployed.

⊛ Live in production

Production-deployed platform with: iOS app on App Store, Android app on Play Store, M2 Refill app on Play Store, PWA live for end-customers, React backoffice live for admins, MQTT-connected vending machines in production (e.g., Gurgaon machine M0078), Zoho Books/Inventory sync active, corporate wallet feature live with real client data (ICAI onboarded), Paytm static/dynamic QR payment live, and multi-role access control active across all surfaces.

How it was built, phase by phase.

8 workstreams across 44 weeks of operated delivery

  1. (001)BUILDWeeks 1–20 (Jul–Nov 2025)

    Corporate Wallet & Company Wallet System

    End-to-end corporate wallet infrastructure enabling companies to fund employee wallets, set spending limits, support cron-based auto-refill, handle refunds.

    ✓ Live corporate wallet feature enabling B2B clients to fund and manage employee vending spend with daily/monthly limits, order history.

    Node.jsReact.jsAndroidiOSPostgreSQLMQTT
  2. (002)BUILDWeeks 1–48 (Jul 2025–May 2026)

    Multi-Platform Frontend (PWA, Admin Backoffice, TS App, M2 Refill App)

    Four distinct frontend surfaces: PWA for end-customers (product browsing, cart, payment, wallet, order history), React backoffice for admins (RBAC dashboard, reports, wallet management, Zoho UI).

    ✓ Four production-deployed surfaces covering all user personas in the vending ecosystem

    React.jsAndroidiOSPWANode.jsApp Store Connect
  3. (003)BUILDWeeks 2–12 (Jul–Sep 2025)

    Role-Based Access Control (RBAC) & Multi-Tenant Architecture

    Hierarchical RBAC system supporting super-admin, admin, wallet client, refill team (shopkeeper, tuck-shop roles), and end-customer roles.

    ✓ Fully role-gated platform supporting super-admin through end-customer with tenant-isolated data and UI

    Node.jsReact.jsJWTPostgreSQL
  4. (004)BUILDWeeks 2–48 (Jul 2025–May 2026)

    Inventory, Warehouse & Refill Management

    End-to-end stock lifecycle from warehouse to vending machine: sub-warehouse creation, stock inward, AVM refill tracking, batch/expiry management, refill history audit trail.

    ✓ Operational inventory system with warehouse-to-machine traceability, field refill app on Play Store, and audit trail per machine/operator

    AndroidNode.jsReact.jsGoogle Play StoreQR Scanner
  5. (005)INTEGRATEWeeks 4–22 (Aug–Dec 2025)

    Multi-Mode Payment Integration (QR, RFID, UPI, PayU, Paytm)

    Integration of multiple cashless payment modes including static and dynamic QR codes via PayU and Paytm, RFID card authentication, UPI payments, and SSE-based real-time payment status updates.

    ✓ Production-deployed multi-modal payment system covering QR (static/dynamic), RFID, UPI, and wallet rails across TS app, PWA, Android, and iOS

    PayUPaytmRFIDUPISSENode.js
  6. (006)INTEGRATEWeeks 4–47 (Aug 2025–Apr 2026)

    IoT Machine Communication via MQTT

    Real-time communication layer between vending machines and backend using MQTT publish/subscribe protocol.

    ✓ Stable IoT backbone enabling real-time machine control, offline alerting, and dispense command delivery at production scale

    MQTTNode.jsIoT brokerEC2SSE
  7. (007)INTEGRATEWeeks 10–22 (Sep–Dec 2025), resumed Apr 2026

    Zoho Books & Inventory ERP Integration

    Bidirectional sync between StackD platform and Zoho Books/Inventory for product (item) management, vendor/client management, sales orders, purchase orders, branch management, invoicing, and CSV export.

    ✓ StackD operations fully mirrored in Zoho Books/Inventory for accounting, procurement, and GST-compliant invoicing

    Zoho BooksZoho InventoryNode.jsReact.jsOAuth2CSV
  8. (008)BUILDWeeks 20–24 (Nov–Dec 2025)

    Promotions, Offers & Loyalty Engine

    Configurable promotional engine supporting BOGO (buy one get one), percentage discounts, flat rupee discounts, combo offers, and quantity-threshold offers.

    ✓ Live promotional engine with BOGO, combo, flat, and percentage discount types tested across all client-facing surfaces

    AndroidiOSReact.jsNode.js

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