Software engineer · front-end & product lead

Fresher to product lead in four years. Still shipping the front end.

I lead the product at a Shopify app company, a ~12-person team, and still own the front end hands-on. I built the dashboard's architecture, a checkout that can't go down, and a React Flow builder shipped in two weeks from an empty repo. React, Next.js, TypeScript, reaching into Laravel when a feature needs it.

See my workGet in touchDownload CV
Abu Hasan Rumi

Open to full-time, contract, and remote. Replies within a day.

Selected work

Given the vague brief and told not to break production.

Each of these was “figure it out, and don't break anything.” The details matter more than the logos.

01DevsNest OPC · 2023–24

Schema-driven widget engine

Replaced hand-coded UI components with a JSON schema and a renderer.

The Dynamatic dashboard (React + Laravel) was built feature by feature by a small team with no shared architecture.

Problem
Every dashboard widget was near-identical hand-written code, built independently. Shipping one took about two weeks, and each copy drifted further from the last: styling bugs, inconsistent props, no shared behaviour.
Approach
A senior pointed me at schema-driven UI. I designed a JSON schema that describes a widget declaratively, and a renderer that turns any valid schema into a live storefront component. Adding a widget became editing one file. The renderer owns layout, theming and edge cases in one place.
Outcome
Build time dropped from ~2 weeks to a day. Other engineers could ship widgets without touching component code, and fixing the renderer once fixed every widget at the same time.

This was the project that changed how I think about UI work. A widget stopped being something you write and became something you describe. The surface area for bugs collapsed once the renderer was solid.

02DevsNest OPC · 2024

Resilient checkout

Error visibility plus a fallback path so a broken component never blocks an order.

Moved from the dashboard to the Dynamatic storefront cart drawer: a handful of merchants, each with a massive customer base. I'd assumed the storefront was the easy half. It wasn't.

Problem
If the cart or checkout button goes down, nobody can pay, and failures were silent. If a component threw, the customer just saw a broken button, and we'd only hear about it through support tickets hours later.
Approach
I read the codebase end to end, asked the person who owned it, and used AI to move faster. Then I added two things: structured error logging that reports the exact failure (message, store, context) to Slack in real time, and a fallback checkout button that always renders, stripped to just “submit the order” so it has almost no way to break itself.
Outcome
Failures now surface in seconds instead of hours, and even during an incident customers can still complete checkout. It reframed reliability for me as something you design for, not only monitor.

The fallback is deliberately dumb. When the real cart throws, we don't try to recover it. We swap in a minimal button whose only job is to submit the order: no upsells, no options, no styling risk. The bar for that path is “money keeps moving,” nothing more.

03DevsNest OPC · 2025

Post-Purchase builder

A visual flow builder and its storefront runtime, built from scratch in two weeks.

A large merchant would migrate from a competitor if we could ship a Post-Purchase product we didn't have yet.

Problem
Post-Purchase offers show after checkout but before the confirmation page, a fiddly surface with strict platform rules. We had nothing built, I'd never worked on it, and it needed a node-based flow editor (React Flow).
Approach
I spent the first days not coding: mapping the competitor's flows, every edge case, and what ours would do differently. Then I built both halves (the dashboard flow editor and the storefront runtime), leaning on platform docs, AI and my teammates for the parts I didn't know.
Outcome
Shipped in two weeks. CEO, CTO, my manager and the merchant all signed off; the migration went through and the merchant stayed. After that the harder briefs started coming to me by default.

The two weeks only worked because week zero went into planning. By the time I opened the editor, the unknowns were small and specific instead of large and scary.

04DevsNest OPC · 2025–present

Recommendation feed, rebuilt live

Turned a basic rules list into a real recommendation engine, with merchants live on it the whole time.

By this point I owned the front-end across five product lines shipping at once. The recommendation feed was the one you couldn't afford to get wrong.

Problem
The existing Rules Feed just showed a static list. Merchants wanted actual recommendations, but they were already running the old version in production, with no maintenance window and no appetite for a regression.
Approach
Same instinct as the checkout fallback, applied to a rollout: ship behind flags, keep the old path alive as a fallback, migrate stores in batches, and verify each merchant on the new engine before switching off the old one. Meanwhile I kept Bundles, Product Options, AB Testing and UGC moving with the team.
Outcome
All five product lines shipped without a single broken store. Over the same year, MRR across the app suite went from $3k to $10k, with a ~12-person cross-functional team I was by then leading.

Leading didn't change the method, just the scale of it: every risky change ships behind a switch, small before big, and merchants hear about it before it lands.

Experience

Where I've been putting the hours.

May 2023 – Present

DevsNest OPC

Software Engineer · front-end / product lead

Joined as a fresher; grew into the senior engineer on a Shopify app suite used by high-traffic merchants, then into leading the product day to day: a cross-functional team of front-end and back-end devs, QA and support. I still own the front-end hands-on.

  • Rebuilt the Dynamatic dashboard's widgets (React + Laravel, no shared architecture) as a JSON-schema system with one renderer. New widgets went from a two-week build to a one-file change, and the whole team could ship them.
  • First Shopify Checkout Extensions work, on Navidium Shipping Protection: made a JS-injected checkout widget install cleanly across the mess of different Shopify themes.
  • Own the Dynamatic storefront cart & checkout UI: real-time error reporting to Slack plus a fallback checkout button that always renders when the main component fails.
  • Built Post-Purchase from scratch in two weeks (a React Flow visual builder and its storefront runtime) to unblock a merchant migration that hinged on the feature. CEO, CTO and the merchant signed off.
  • Drove the front-end across five product lines (Bundles, Product Options, AB Testing, UGC, a rebuilt recommendation feed); MRR across the suite went from $3k to $10k in a year, with no broken stores.
  • Lead a ~12-person cross-functional team (front-end, back-end, QA, support), plan architecture with the CTO, and talk to merchants directly rather than through a PM, while keeping the front-end my own hands-on work.
  • React
  • TypeScript
  • Next.js
  • Laravel
  • Shadow DOM
  • React Flow
  • Checkout Extensions

2021 – 2023

Independent

Freelance & personal projects

Front-end-led products before and around my first job: some for real users, some to learn a tool properly.

  • Shipped an offline-first PWA for a student house to manage shared meals and balances (React + Firebase).
  • Built a gamified LMS with AI-generated quizzes, an accessibility-first form builder, and a Chrome extension that extracts design tokens from any page.
  • Comfortable taking a project from empty repo to deployed: UI, state, data model, auth, CI.
  • Next.js
  • Prisma
  • PostgreSQL
  • React Native
  • Firebase

Beyond the code

Learns by asking
First instinct on anything new is questions and a slow read of the codebase, not a guess.
Owns mistakes
When something I shipped goes wrong, I say so first, fix it, and fold the lesson into how I work. It's why I ship small and safe now.
Calm under pressure
The fear of a big deploy turned into a process I can hand to other people: learn, ship small, ship big.
Talks to the people using it
Direct lines to merchants about their problems, not a game of telephone through a PM.

What I work with

Front-end first, and fluent enough everywhere else to ship on my own.

I go deep on the interface: state, motion, accessibility, the slow network, the code the next person reads.

Core

  • JavaScript
  • TypeScript
  • React
  • Next.js
  • HTML
  • CSS

Front-end craft

  • Tailwind CSS
  • Framer Motion
  • GSAP
  • Redux
  • Zustand
  • Web Components / Shadow DOM
  • Design systems
  • Accessibility (a11y)
  • Web performance
  • PWAs
  • Responsive / cross-browser

AI in the workflow

  • Claude / GPT for scaffolding & review
  • Prompt design
  • LLM API integration
  • AI features (quizzes, assist flows)
  • Cursor / agentic editors

Reaching into the back end

  • Node.js
  • Express
  • GraphQL
  • REST
  • PostgreSQL
  • Prisma
  • Firebase
  • Shopify APIs

Praise

What the people who led the team say.

Two LinkedIn recommendations: from the product lead I worked with directly, and the senior engineer who mentored me early on.

“I had the pleasure of working with Rumi while leading a product team, and his performance was nothing short of exceptional. Rumi consistently delivered high-quality work, showed strong ownership, and brought a sharp problem-solving mindset to every challenge. He's proactive, reliable, and a true team player — someone you can count on to elevate any project. Highly recommended.”

MD Zulhaz Uddin Joy

Led the product team Rumi worked on

May 2025

“Such a nice guy who is always eager to learn and listen. I have directly worked on a project with him and he was a great team player too.”

Opu Hasnat

Senior on the Dynamatic team, now Technical Writer @ CHEQ

June 2024

See all recommendations on LinkedIn →

More projects

Things I've built to learn, and kept because they work.

React · Firebase

Pakhir Basa

PWA for a student house: shared meals, bazaar runs and running balances. Google login, invite codes, works offline.

Next.js · Prisma · Postgres

Edulance LMS

A learning platform that behaves like a game: AI micro-quizzes, squads, streaks and certificates.

React · Zustand · Tailwind

FlexiForm

Modular form builder with conditional logic. Build on the left, watch it render live on the right.

React · Chrome APIs

WebPeekr

Chrome extension that pulls the fonts, colours and design tokens out of any page you're looking at.

React Native · Expo

Expensify RN

Dark, animated expense tracker built with Reanimated and Expo Router.

Notes

Recent notes

See all notes

About

I'm Rumi, a software engineer from Dhaka who likes shipping real things.

I joined my first job as a nervous fresher with a folder of pet projects and no idea how a real team ships. So I asked a lot of questions and read a lot of code line by line. A few years later I was leading the product, a cross-functional team, while still writing the front end myself.

It wasn't a straight line. I broke something real in production early: a client integration went down because of me. I owned it, fixed it, and proved the lesson on a harder problem. That's where “ship small, ship safe” comes from. I care about the parts of the front end that don't show up in a demo: the empty state, the error state, the slow network, the code the next person has to read.

I work with AI in the loop for scaffolding and review. The architecture and reliability calls stay mine. Day to day I also lead a small cross-functional team, which mostly means making sure the people around me can do their best work and get paid properly for it.

Off the clock it's cricket, too much chai, and mountain trips with friends. I think teams that spend real time together build better software.

Abu Hasan Rumi on a mountain trip
Name
Abu Hasan Rumi
Based
Dhaka, Bangladesh
Focus
Front-end craft and system design, leaning into product
Currently
Software Engineer at DevsNest OPC, leading the product
Looking for
A full-time engineering role (contract & remote also open)
Languages
English, Bengali

Contact

Let's talk. I'm looking for a full-time engineering role.

Full-time

The main thing I'm after: product teams in Dhaka or remote that care about front-end craft and shipping safely.

Remote

Long-term remote roles with real timezone overlap.

Contract

Open to scoped freelance builds too: web apps, Shopify apps, MVPs.

The fastest way to reach me is email or a quick call. No pitch, no pressure, just tell me what you're building.

hello@itsrumi.comBook 15 min
LinkedInGitHub