Each card below opens a detailed, story-style case study: business context, constraints, architecture, execution, and impact. Together they show how I design, ship, and stabilise production systems in very different domains — from government SaaS and payment gateways to media CMS, logistics, IVR, and ecommerce.
Who, what, and why — business stakes and constraints.
Architecture, decisions, and delivery approach per case.
What changed for users, stakeholders, and the business.
High-impact bug fixes and feature work on the Ami-Probashi MoEWOE–BMET platform (~7M records), improving reliability for a national migrant database and protecting a multi-year government revenue channel.
Built and shipped a multi-tenant news portal/CMS using Next.js, TypeScript, Laravel, MongoDB, and MySQL, then commercialised it with paying media clients (e.g., Daily Niropekkho), validating product–market fit.
Resolved critical payment gateway failures in a PHP/Laravel/Vue stack, restoring successful transactions and contributing to stronger customer trust and new customer acquisition for a Bangladeshi payment gateway.
ShurjoPay experienced BRAC Bank–specific transaction failures because the encryption/token generation library provided by BRAC Bank was built for PHP 7, while ShurjoPay’s production runtime had moved to PHP 8. When the PHP 7 library was directly require-ed in PHP 8, transaction requests were not encrypted correctly, causing failures for users paying with BRAC Bank cards/accounts.
Analysed ~100M historical click records to build a Laravel-based system that predicts CPC/CPA/CPM bids for bulk click purchases, helping stabilise revenue and bidding strategy in a high-volume ad environment.
Built and shipped a freight forwarding operations portal with Django, React, and PostgreSQL to automate AWB and BL generation, reducing manual paperwork and errors and commercialised it with Navana Logistics as anchor customer.
Delivered critical production bug fixes for a US healthcare plan operations portal used by agents, stabilising enrolment and policy workflows and protecting recurring revenue tied to US government contracts.
Designed and implemented an IVR system using Twilio APIs and Asterisk to automate inbound call routing and self-service flows, reducing manual call handling and improving customer support efficiency.
Built a PHP + eBay API inventory tracker and packing slip automation tool that streamlined fulfilment and operations, enabling a dropshipping business to scale to roughly $60K in monthly revenue without proportional headcount.
Built a PHP/osTicket-based prototype ticketing system with email notifications for IIG stakeholders, showing how network incidents could be tracked, routed, and communicated more systematically across NOC and partners.
After successful credential authentication the app did not redirect the user back to the original page. The sign-in flow produced a session cookie (Auth.js / NextAuth), JWT callback logged, but the session callback did not run and middleware outputs were absent. Pages that should be protected were accessible without authentication.
Deep dive into the Notion-like Kanban migration from React Context to Zustand, cutting ~70% unnecessary re-renders and eliminating the RunningTasksBar dock flicker through selector-based subscriptions and better hydration.
Step-by-step implementation guide for replacing React Context/useReducer with a Zustand store: migration checklist, file diffs, selector hooks with shallow comparison, and updated tests for a Notion-style board.
Root-caused task drawer flicker to Next.js router.replace remounting server components; fixed by switching to window.history.replaceState for URL syncing, keeping SPA behavior while preserving deep links and back/forward navigation.