SUMIT KUMAR
Designing scalable backend systems and distributed architectures utilizing Event-Driven Microservices, Domain-Driven Design (DDD), CQRS, and Event Sourcing, while integrating Stripe Connected Account/Paymongo payment flows and exploring agentic AI/ML structures.
func PublishEvents() {
events := db.GetOutbox()
for _, ev := range events {
broker.Publish(ev)
db.MarkSent(ev.ID)
}
}
About Me
Core Background & Expertise
Hello! My name is Sumit Kumar (Birwal). I design resilient, decoupled, and distributed software systems. My engineering focus lies at the intersection of robust backend patterns and secure web integrations.
I specialize in backend architecture utilizing Domain-Driven Design (DDD), CQRS, Event Sourcing, and Event-Driven Architectures (EDA). I focus on transaction integrity using patterns like the Inbox-Outbox Pattern with RabbitMQ to guarantee reliable event delivery. On the integration layer, I design payment architectures including Stripe Connected Account architectures and local gateways like Paymongo Philippines.
I am continuously improving my system design thinking, writing cleaner architectures, and exploring AI/ML agentic systems to solve real-world problems.
Backend Architecture
DDD, CQRS, Event Sourcing, Microservices
Reliable Messaging
RabbitMQ, Inbox-Outbox Pattern, Saga
Payment Gateways
Stripe Connect, Localized E-wallets, Escrows
Problem Solving
Data Structures, Algorithms (C++/Python)
Professional Experience
My corporate journey, software engineering roles, and technical project execution.
Full Stack Developer
Zenmonk Software & Services- Engineered highly scalable backend services using NestJS, Next.js, React, and TypeScript.
- Implemented core system architectures including Domain-Driven Design (DDD) and CQRS (Command Query Responsibility Segregation) to isolate workloads.
- Designed and executed Event Sourcing ledgers and transactionally secure event brokers using the Inbox-Outbox Pattern with RabbitMQ.
- Orchestrated inter-service async communication, containerizing domains via Docker into distributed microservices.
- Worked closely with senior architects in Agile environments, driving code reviews, testing routes in Postman, and merging branch components.
Node.js Developer
Techbuilder- Specialized in backend service design and API integrations using Node.js and Express.
- Designed and implemented secure billing and payment channels utilizing Stripe Connected Account architectures for split payout vendor structures.
- Integrated localized payment networks including credit card gateways and mobile e-wallets (GCash, GrabPay) using the Paymongo Philippines API.
- Standardized integration testing profiles, verifying payload schemas and validating routes in Postman.
MERN Stack Intern
CodeQuotient- Developed full-stack web applications utilizing the MERN (MongoDB, Express, React, Node.js) stack.
- Solidified basic algorithms, computer science paradigms, and database relations.
- Completed over 120+ Data Structures & Algorithms (DSA) challenges on LeetCode using C++ and Python.
- Coordinated with cohort engineering leads to test, debug, and launch responsive user interfaces.
Architectural Journey
My evolution from building traditional monolithic CRUD applications to designing complex, decoupled, and distributed systems.
MERN Monoliths (MVC)
Began building standard web apps using the MERN stack with monolithic MVC architecture. While great for learning, I quickly faced bottlenecks like tight code coupling, coordination conflicts, and difficult scaling as codebases grew.
Service Isolation & Separation
Shifted focus towards domain modularity. Began splitting routers, controllers, and database access logic into distinct, isolated layers, reducing dependency conflicts and improving codebase maintainability.
Microservices Architecture
Adopted Microservices architecture to isolate services, enable independent scaling, and isolate failure domains. Utilized RESTful communication and orchestrated containers with Docker.
DDD, CQRS & Event-Driven Systems
Deep-diving into robust architectural paradigms: Domain-Driven Design (DDD) to map complex business boundaries, CQRS to segregate command and query workloads, Event-Driven Architecture (EDA) via RabbitMQ, and the Inbox-Outbox pattern for resilient message delivery.
Featured Projects
A showcase of technical repositories demonstrating advanced backend architectures, transaction patterns, payment engines, and AI/ML integrations.
Inbox-Outbox Pattern Broker
A transactionally secure microservices messaging system implementing the Inbox-Outbox pattern using NestJS, PostgreSQL, and RabbitMQ to guarantee at-least-once message delivery.
View Repository
Event Sourcing POC
An event-sourced backend proof-of-concept built with NestJS. Stores chronological, immutable system state transitions, supporting event replays, audits, and CQRS handlers.
C++ Custom Web Crawler
Built a web crawler in raw C++ using my own generic string, linked list, and hashmap libraries — completely avoiding external dependencies or standard string methods. It gave me full control over memory management, performance, and data structures, designed for low-level efficiency and zero unnecessary overhead.
Custom C++ Library Suite
Designed and engineered generic C++ data structure and utility libraries from scratch, including custom implementation of HashMap, LinkedList, and String classes with manual memory management and optimized search-complexity bounds.
LinkedIn Clone
A full-featured LinkedIn clone platform designed to explore scalable backend messaging, post feeds, user network relations, dynamic updates, and connection search graphs.
Modular Monolith to Microservice
A comprehensive architectural migration POC detailing the separation of tightly coupled monolithic subdomains into Dockerized event-driven microservices.
LangChain AI Agent POC
An intelligent agentic POC exploring AI frontiers using LangChain libraries, LLM function calling, memory layers, and custom tool binding architectures.
RabbitMQ Exchanges POC
A message routing architecture implementing Direct, Topic, and Fanout exchanges in RabbitMQ for asynchronous multi-service event orchestration.
AI Problem Analyzer
An intelligent engineering assistant leveraging LLM APIs to ingest system bug reports and synthesize detailed architectural design reviews and debugging paths.
AI Resume Customizer
A responsive application using prompt engineering to dynamically parse candidate profiles and customize CV blocks to match targeted corporate job specifications.
Technical Skills
Categorized layout of technologies, programming languages, and core software architecture designs I specialize in.
Architectural Paradigms
Languages & Backend Engineering
C++
Python
JavaScript
Django
DSA & OOP
Java
NestJS
Node.js / Express
Databases & Infrastructure
MongoDB
MySQL
PostgreSQL
Redis
BullMQ
Socket.io
RabbitMQ
TypeORM
Mongoose
Docker
Linux (CLI)
Git
GitHub
Frontend & Tools
HTML5
CSS3
React
Tailwind CSS
Redux
Redux Toolkit
Zustand
Postman
HeroUI
Ant Design
React Hook Form
Zod
Payment Gateways
Stripe
Razorpay
Paymongo Philippines
Cloud & Deployment
Vercel
Render
Railway
Netlify
InfinityFree
Aiven
Achievements & Leadership
Key technical milestones, coding victories, and leadership initiatives that shaped my discipline.
Technical Milestones
1st Place – On-Spot Coding
Zerone24 IT FestCompeted in real-time to solve complex algorithmic puzzles under high pressure. Showcased strong logical layout and execution speeds.
2nd Place – On-Spot Debugging
Zerone24 IT FestDiagnosed, verified, and resolved runtime errors, design logic vulnerabilities, and syntax faults in competitive code layouts.
Community & Volunteering
NCC (National Cadet Corps) Cadet
School Service DivisionTrained in systematic physical discipline, defense values, and collaborative operations. Formed solid team-centric focus and resilience.
NSS (National Service Scheme) Volunteer
College Service DivisionContributed to civic campaigns, local welfare drives, and social welfare programs, developing strong soft skills and collaborative empathy.
Hobbies & Interests
What I enjoy doing when I am not coding or building distributed systems.
Cooking
Experimenting and preparing unique, creative dishes in the kitchen.
Watching Movies
Enjoying mind-bending sci-fi, cinema classics, and insightful documentaries.
Badminton
Engaging in energetic, fast-paced matches on the court.
Gaming
Casual relaxation and competitive match-ups with friends.
Get In Touch
Have an interesting project or opportunities you'd like to discuss? Drop a message!
Let's collaborate.
I am open to discuss full-stack engineering roles, system architecture design opportunities, and AI/ML project collaboration. Feel free to contact me through the form or direct networks.
Haryana, India