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Jai Jhamb
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Commerce · 2026 · Client work at ABS Infotech

E-Commerce

End-to-end commerce platform spanning customer, staff, and admin workflows.

React · TypeScript · NestJS · MySQL · Capacitor · Docker

01Problem

A customer app and an admin app with staff views, both backed by one API that owns prices, stock and media.

Shopping, product and inventory management, staff operations and admin work had to run as one system, on phone and web.

02My role

Primary developer

03What I built

  1. Customer app

    React · Capacitor for mobile

    Admin app

    React · staff views

    REST

  2. Backend

    NestJS · TypeORM

  3. Database

    MySQL

    Media

    S3

    Packaged with Docker

  4. Cloud

    AWS Elastic Beanstalk

Both apps talk to one backend. It decides every price and serves every file — nothing in storage is public.
  • A customer app packaged for mobile with Capacitor, and an admin app with staff views.
  • Product management, inventory tracking and QR scanning.
  • Staff permissions set per system and per order type, checked on the server.
  • Item photos and videos uploaded from the camera or the gallery in the staff app.
  • Order creation and order history for customers.
  • Product images and videos stored on S3.
  • Docker images deployed on AWS Elastic Beanstalk.

04Engineering decisions

    • Option A

      The totals the client sends

    • Option BChosen

      The server, from stock data

    Trade-off
    Trusting the client is less code. Computing server-side needs a lookup per item, but the request body can’t set its own price.
    Decision
    Totals come from server-side stock prices. Body prices are ignored, every field is validated, and orders are rate-limited per phone.
    Why
    It closes price tampering, and bad input gets a clear 400 instead of an opaque 500.

    • Option A

      A public S3 bucket with CORS

    • Option BChosen

      A backend proxy

    Trade-off
    Direct S3 links skip a hop. A proxy adds load to the API, but nothing has to be public.
    Decision
    Media is served through the backend, with a local-disk fallback for older files.
    Why
    No public bucket, no CORS rules, and pre-migration files keep working.

05What I learned

Correctness and security live behind the UI. Server-side pricing, sign-in timing and media handling showed me how small assumptions become production bugs.

06Links