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SMSUJAN

Available for workDhaka, Bangladesh

Software Engineer · Full-Stack JavaScript · SaaS Product Delivery

I ship multi‑tenant SaaS end to end.

Three-plus years of professional experience building commercial SaaS in production. Two products I have owned are live on the Shopify App Store — one at five stars — covering subscription billing, tenant onboarding, webhook reliability and customer-facing analytics.

S M SUJAN — portrait

SpeedCart is live on the Shopify App Store with a 5★ rating from merchant reviews.

Stack

  • TypeScript
  • JavaScript
  • React
  • Next.js
  • Remix
  • Node.js
  • Express
  • GraphQL
  • REST
  • Prisma
  • Sequelize
  • PostgreSQL
  • MongoDB
  • MySQL
  • Vue.js
  • Nuxt.js
  • Tailwind CSS
  • Ant Design
  • AWS S3
  • AWS Lambda
  • Jest
  • React Testing Library
  • Claude Code
  • GitHub Copilot
3+
Years in software

3+ in commercial SaaS

2
Products live on the App Store

Owned end to end

5.00
Merchant rating

SpeedCart, Shopify App Store

20+
Technical interviews

Conducted at OctiDev

01About

What I actually do all day.

I'm a full-stack JavaScript engineer with 3+ years of professional experience delivering multi-tenant SaaS products end to end — design, implementation, release, and the maintenance that comes after. I have independently owned and shipped two commercial SaaS applications now live on the Shopify App Store, covering subscription billing, tenant onboarding, webhook reliability, and customer-facing analytics.

Most of my work sits on the boundary between product and infrastructure: PostgreSQL schemas designed via Prisma to model merchant configuration and order workflows across tenants, OAuth 2.0 authorisation and JWT session handling for embedded third-party applications, PII handled under strict data-protection requirements, and queue-based webhook ingestion re-architected around idempotency so no inbound traffic is lost.

On the product side I build the tooling customers actually touch — a drag-and-drop form builder and template system in React, a two-step onboarding flow from Figma handoff, an upsell engine with per-product and collection-level targeting, and analytics surfacing order and conversion metrics. The current app serves merchant storefronts in nine languages.

I'm comfortable debugging in unfamiliar codebases, I keep Jest and React Testing Library coverage on critical flows, and I use Claude Code and GitHub Copilot daily for scaffolding, refactors and test generation — at the same review and test standard. I have onboarded four interns and junior developers and conducted 20+ technical interviews.

I currently work fully remote on an async international team, in English, across time zones.

  • 01

    Product delivery

    Ambiguous requirements broken into scoped, estimable work, then designed, built, released and maintained — with progress and blockers communicated async across time zones.

  • 02

    Backend & data

    PostgreSQL schemas modelling real business workflows via Prisma, REST and GraphQL APIs, OAuth 2.0 and JWT sessions, and queue-based async processing with idempotency guarantees.

  • 03

    Frontend & product UI

    React, Next.js and Remix interfaces with reusable components and predictable state — drag-and-drop builders, template systems, onboarding flows and customer-facing analytics.

02Career

Where I am now

The current role, and what it has involved so far.

Full-Stack Engineer · Normalize

August, 2025Present

  • Independently owned Better COD Form & Upsells from design through production release — a multi-tenant SaaS application now live on the Shopify App Store, serving merchant storefronts in 9 languages.
  • Broke down ambiguous client requirements into scoped, estimable work; communicated progress, trade-offs and blockers asynchronously across time zones.
  • Built tenant-facing configuration tooling — a drag-and-drop form builder and template system in React — giving each merchant independent configuration without code changes.
  • Designed PostgreSQL schemas via Prisma to model merchant configuration, order and offer workflows across tenants.
03Projects

Selected work

Commercial products with paying users, and what I owned on each.

  1. 01

    Better COD Form & Upsells — Multi-Tenant SaaS

    A multi-tenant cash-on-delivery order-form and upsell application, live on the Shopify App Store and serving merchant storefronts in 9 languages. I owned it end to end: tenant onboarding, a drag-and-drop configuration builder and template system, the offer engine with per-product and collection-level targeting, order analytics, multi-pixel event tracking, and localisation.

    • React
    • Remix.js
    • Node.js
  2. 02

    SpeedCart — Subscription SaaS, Cart Recovery

    A subscription SaaS product for abandoned-cart recovery, live on the Shopify App Store with a 5★ customer rating. I led delivery from design to production — subscription billing with a free-trial flow, tenant provisioning, and a queue-based webhook pipeline with idempotency guarantees that sustained all inbound traffic with zero data loss.

    • Remix.js
    • React
    • Node.js
  3. 03

    Returns Management System

    An end-to-end returns workflow spanning RMA, refunds and restocking. The hard part was not the UI: it was translating wildly varied customer return policies into configurable business rules and the schemas that support them, so a merchant could express their own policy without a code change.

    • Remix.js
    • Node.js
    • GraphQL
04Writing

Writing

Notes on shipping software, and the occasional lesson learned the hard way.

The short version

Everything above, on two pages.

Roles, dates, the stack behind each product, and what actually shipped. Opens in Google Drive.