Jubayer Hossain

I built the Flutter app, marketing site, and admin end-to-end. I owned the NestJS API with other engineers on the backend.

Surfaces

• One Flutter app with role-correct shells (player, coach, club, league, scientist) instead of five client codebases.
• NestJS as the source of truth for billing and health so the app never invents a paid or scored state.
• Encrypt sensitive payloads on the device and pin TLS — health and payments are treated as adversarial, not as a launch checklist.

I took the storefront from scaffold to a live shop, owned the FastAPI commerce API, and ran admin and production ops.

Surfaces

• Cookie sessions with CSRF instead of tokens in JavaScript — required for a real checkout and admin on production domains.
• Payments as a state machine: signed webhooks, atomic stock, emails, and retry — not a Checkout.js snippet.
• One FastAPI surface for storefront and admin, split by domain (catalog, orders, cart, coupons, shipping), not by client.

I built the patient app, caregiver app, and tenant/super-admin console end-to-end. I owned the NestJS API with other engineers on the backend.

Surfaces

• One patient codebase with per-tenant flavors instead of a fork per organization.
• The care loop is one product across patient app, caregiver app, and console — not a patch on a single surface.
• Billing is gated: no payment recorded until an invoice exists, with GST split correctly for Indian orgs.