Backend Systems | Full Stack Apps | Real-Life Project Delivery

building systems that scale.

Hi, I am Saurabh Kumar Singh, a Software Engineer working across Java, Spring Boot, microservices, and Oracle DB on the backend, and React, Node.js, and MongoDB on the frontend — with hands-on experience in UPI systems, distributed architectures, and payment workflows.

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Current Focus

Backend & Microservices

Primary Stack

Java, Spring Boot, MERN

Domain

Payments, UPI, Distributed Systems

backend-runtime.yml

>role: backend-focused-full-stack-developer

>backend: java + spring-boot + microservices

>frontend: react + responsive-ui

>data: oracle-db + mongodb + redis

>domain: payments + upi + distributed-systems

>tools: postman + docker + kubernetes + kafka

Request Flow

UI to API to backend to database

React UI

REST / SOAP API

Java + Spring Boot

Oracle DB / MongoDB

UPI

Payment logic

30K TPS

Scale delivered

Current Work

Backend systems and full-stack apps for real business problems.

I build systems end to end: scalable backend services, secure API layers, database-backed workflows, responsive React screens, and reliable payment or transaction logic when a project needs it.

Backend microservices at scale

Building Java and Spring Boot microservices for UPI transaction workflows, handling 20K–30K TPS with Eureka Server-based service discovery.

Payment & UPI reliability

Working on backend modules for a large-scale banking platform, reducing production incidents across transaction workflows.

API validation & automation

Testing and validating 50+ REST/SOAP endpoints with Postman, backed by an internal Java-based automation framework.

Full stack & ML side projects

Shipping React/Node full-stack apps and ML-driven tools, including a BERT-powered semantic search engine.

Technical Focus

The technologies behind my work.

Backend microservices

Java & Spring Boot

Distributed systems

System design

UPI & payment systems

REST & SOAP APIs

Oracle DB

Kafka

Docker & Kubernetes

Redis

MERN stack development

React frontends

Node.js APIs

MongoDB

Authentication

Admin dashboards

API validation & testing

AI-native development

Data structures & algorithms

Saurabh Kumar Singh

Full Stack Developer | Java, Spring Boot, MERN, Microservices

1+ Yrs

Professional experience

30K

TPS scale delivered

1418

Codeforces max rating

10+

Real-time projects

Featured Work

Projects backed by problem solving.

See all projects

TF-IDFBERTSemantic SearchNLP

Coding Problem Search Engine (TF-IDF + BERT)

A semantic search engine that ranks coding problems using TF-IDF, BERT embeddings, and contextual similarity. Indexes 10K+ problems across LeetCode, Codeforces, CodeChef, and HackerRank, improving search relevancy by 48% over keyword-only ranking.

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Node.jsExpressMVCREST APIs

Job Portal Application

A backend service for a two-role (recruiter and candidate) job portal built with Node.js and Express, following an MVC architecture with 10+ RESTful endpoints for job postings and applications, plus middleware for request validation.

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BlogMERNContentCRUD

Tech-Blog

A publishing platform for technical articles across programming, AI, and cybersecurity with reader and author workflows.

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FinanceAuthDashboardMongoDB

Smart Expense Tracker

A budget management tool for tracking personal expenses with secure authentication and organized financial records.

View repository

Achievements

Competitive programming proof.

The portfolio should communicate more than tools. These signals show consistency with data structures, algorithms, ranking pressure, and contest-style problem solving.

Specialist at Codeforces with a maximum rating of 1418.

Achieved Global Rank 130 in CodeChef Starters 82 Division 3 among 9342 participants.

Winner of DSA Craft competition organized by MKSSS's Cummins College of Engineering.

Qualified for the Finals of CODEFT Solutions coding competition at AIT Pune.

Shortlisted for the Education Scholarship Scheme for Army Personnel (ESSA) for AY 2022–23 and 2023–24.

Toolkit

Technologies I use in real work.

Java

Spring Boot

Microservices

Eureka Server

System Design

MongoDB

Express.js

React

Node.js

JavaScript

REST APIs

SOAP APIs

Python

C++

SQL

Oracle DB

Redis

Kafka

Docker

Kubernetes

UPI & Payments

Postman

API Testing

Git

Linux

AI-native Development

JFrog

Problem Solving