RKB
Md Abdur Razzak

Md Abdur Razzak Full-Stack Engineer

Building scalable, high performance web applications & APIs end-to-end. Building scalable web applications end-to-end. Solving problems that matter.

ReactNext.jsTypeScriptNode.jsMongoDBPostgreSQLRedisBullMQRabbitMQNGINXLoad BalancerAI AgentDocker
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Dhaka, Bangladesh
Md Abdur Razzak - Full-Stack Engineer

Md Abdur Razzak

Full-Stack Engineer

Available
2+ Yrs Experience

About Me

Passionate about building fast, intuitive web interfaces and scalable backend infrastructure.

I'm a Backend-focused Full Stack Developer with 2+ years of experience building and shipping scalable web applications from end to end. I've contributed to 10+ live products, working across backend architecture, APIs, databases, frontend interfaces, and production deployments.

My core strength is building robust backend systems with Node.js, TypeScript, Express.js, MongoDB, PostgreSQL, and Redis, while also creating responsive and intuitive interfaces with React.js and Next.js.

I also use AI-assisted development and modern frontend tools to design and build clean, user-friendly interfaces faster without compromising code quality or maintainability. I enjoy turning real-world requirements into reliable products, optimizing performance, and solving production system challenges.

When I'm not building software, I'm exploring new technologies, AI tools, system design, and better ways to build products that are fast, scalable, and genuinely useful.

2+

Years Experience

10+

Live Products

100%

Production Ready

Clean Frontend Architecture

Building modular, reusable React and Next.js components with strict TypeScript types and responsive design systems.

Robust API Integration

Designing and consuming RESTful and real-time WebSockets APIs with predictable state management and error handling.

Performance & DX Optimization

Optimizing render cycles, bundle sizes, database queries, and caching to ensure fast loading times across devices.

Production Ready

Writing maintainable code tested for edge cases, containerized with Docker, and deployed via reliable CI/CD pipelines.

Skills & Technologies

Core technologies and frameworks I use to build scalable web applications.

Languages

  • JavaScript (ES6+)
  • TypeScript
  • C / C++

Backend & APIs

  • Node.js
  • Express.js
  • Nest.js
  • BullMQ & RabbitMQ
  • REST APIs & Webhooks
  • Stripe Integrations

Databases & Storage

  • MongoDB (Mongoose)
  • PostgreSQL (Prisma)
  • Redis
  • VectorDB

AI & LLM

  • LangChain & LangGraph
  • OpenAI & Gemini SDK
  • LLM Integration

Frontend

  • React.js
  • Next.js
  • Tailwind CSS

DevOps & Cloud

  • Docker
  • NGINX & Load Balancing
  • Cloudflare & R2
  • DigitalOcean
  • Git & GitHub

Projects

Production-grade full stack projects tackling real-world challenges, not tutorials or todos.

Dating & Social

Vivaleve

Dating & Social Platform for STI Community

A privacy-first modular monolithic backend API and real-time social engine for individuals living with STI conditions (HPV, HIV, HSV-1/2)—enabling match discovery via swipes, post feeds, winks, blogs, events, first-date ideas, and Stripe-powered premium messaging and private albums.

Flushes thousands of buffered social interactions per minute with sub-20ms database queries
TypeScriptNode.jsExpress.jsMongoDB+8
Operations

Stone Portal

Enterprise Field-Service & Operations Platform

A robust backend API and real-time operations engine for landscaping and field-service enterprises—handling estimates, automated invoicing, project scheduling, crew attendance, payroll, equipment dispatch, and Stripe one Time payment.

Processes async background jobs & real-time crew dispatches with sub-20ms database queries
TypeScriptNode.jsExpress 5PostgreSQL+7
Marketplace

Ooh Ahh

On-Demand Beauty Service Platform

A location-based service marketplace connecting users with nearby beauty professionals, similar to an Uber-style booking system for salon and home services.

Handled real-time booking workflows with low-latency updates
Node.jsExpress.jsMongoDBRedis+4
Rental Services

SELE

Car Rental Platform in USA

A rental app that allows agencies to list cars for rent and users to rent them with real-time booking and payment. Includes in-app messaging between agencies and renters.

Handled multiple concurrent rentals with instant booking confirmation
Node.jsExpress.jsMongoDBSocket.io+2
Marketplace

Re-Wears

B2C Marketplace in Dubai

A Dubai-based e-commerce platform where users can buy and sell products. The platform supports in-app messaging, notifications, and real-time booking for products or services.

Scalable platform with real-time communication and transactions
Node.jsExpress.jsMongoDBSocket.io+2
Real Estate

Project Finder

Real Estate Agency Platform

A subscription-based real estate platform that allows users to discover and browse properties. Users receive notifications from admins, use advanced filters, and access premium listings after subscribing.

Thousands of property views per month with real-time updates
Node.jsExpress.jsMongoDBRedis+3
Marketplace

263ProLink

Service Marketplace Platform

A platform where users can provide and receive services. Supports subscription-based access, one-time payments, and real-time communication.

Facilitated seamless service transactions with real-time communication
Node.jsExpress.jsMongoDBSocket.io+2
Operations

Stone Portal

Stone Portal

Processes async background jobs & real-time crew dispatches with sub-20ms database queries

Enterprise Field-Service & Operations Platform

A robust backend API and real-time operations engine for landscaping and field-service enterprises—handling estimates, automated invoicing, project scheduling, crew attendance, payroll, equipment dispatch, and Stripe one Time payment.

System Design & Architecture Pattern

Pattern: Modular Monolith with Feature Slices, Prisma ORM & BullMQ Queue Workers

Architectural Choice Rationale: Maintains clear domain boundaries across feature modules while offloading CPU-bound tasks (PDF generation, bulk attendance calculations, email notifications) to isolated BullMQ Redis workers.

Key Architectural Highlights

  • Vertical slice module scaffolding isolating controller, service, route, and Zod schema per feature domain
  • BullMQ worker pool backed by Redis with exponential backoff retry strategies (3 attempts)
  • Stripe webhook pipeline registered prior to body parsing for raw-buffer signature verification

Technical Challenges & Engineering Solutions

Challenge #1

Heavy CPU operations (PDF invoice rendering, bulk payroll calculations, email dispatch) caused HTTP event loop lag.

Resolution & Engineering Solution

Architected asynchronous BullMQ queues backed by Redis, offloading intensive tasks to isolated worker threads with exponential backoff retries and graceful shutdown handlers.

Challenge #2

Stripe webhook signature verification failures caused by Express automatic JSON body parsing.

Resolution & Engineering Solution

Mounted the raw-body Stripe webhook route (/api/stripe/webhook) prior to global express.json() middleware, guaranteeing uncorrupted payload verification.

Work Experience

My professional engineering journey building web applications and full stack services.

Full Stack Developer

Spark Tech Agency

2025 - Present

Architecting and delivering full stack web applications and scalable microservices for B2B SaaS and B2C platforms. Built responsive React/Next.js user interfaces integrated with robust Node.js, Express, and MongoDB backends. Improved API & page load performance through query optimization, SSR, and Redis caching. Implemented background job processing with BullMQ, SMS/SMTP services, and containerized deployments with Docker.

Node.jsExpress.jsMongoDBRedisBullMQDockerCI/CDMonorepo

Frontend Developer Intern

FKR IT

2024 - 2025

Worked primarily on frontend development using React and Next.js, building responsive and user-friendly interfaces. Collaborated with backend teams to integrate RESTful APIs and contributed to small backend services when needed. Focused on performance optimization and clean UI architecture.

ReactNext.jsTypeScriptTailwind CSSREST APIGitHub Actions

Get in Touch

Interested in working together or discussing potential opportunities? Let's connect.

Whether you have a specific role, project collaboration, or architectural question in mind, feel free to reach out.