Rohit Singh

Delhi, India  ·  Open to backend roles

Rohit Singh

Backend Java Developer · Spring Boot · Microservices

I design and optimize REST APIs on the JVM — cutting response times on 100K+ record datasets by 30% and query execution by 25%. Four years across government-scale and enterprise systems, mostly where the database is the bottleneck.

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Portrait of Rohit Singh
4+years building
backend systems
30%faster API response
on 100K+ records
50%less processing time
on report generation
80%storage reduction
on a national scheme

01 / About

I make slow backends fast, and fragile ones dependable.

I'm a backend Java developer based in Delhi with 4+ years designing and optimizing high-performance REST APIs using Java, Spring Boot and PostgreSQL. Most of my work lives behind the scenes: query plans, indexes, transaction boundaries, and the API contracts that everything else depends on.

I've built scalable microservices with secure authentication using JWT and role-based access control, deployed applications across AWS and Linux server environments, and spent a lot of time doing database performance tuning and query optimization — the unglamorous work that turns a 30-second report into a 15-second one.

My work has shipped at both ends of the spectrum: a Government of India scheme under the Ministry of Food Processing Industries serving national-scale workflows, and private enterprise products like ESOP management and event platforms. Different constraints, same discipline — scalability, reliability, security, and backend systems someone else can still maintain later.

02 / Experience

Where I've worked

  1. Nov 2024 — Present Current

    Java Developer · Quantam Asia Pvt. Ltd

    • Designed, developed and optimized RESTful APIs using Java 8 and Spring Boot handling large datasets (100K+ records), reducing response times by 30% and improving overall application scalability.
    • Analyzed and optimized complex PostgreSQL queries using indexing and query refactoring, achieving a 25% reduction in execution time.
    • Integrated third-party APIs and internal services, ensuring secure and reliable data exchange across distributed systems.
    • Deployed and maintained production applications on cloud-based Linux servers (Ubuntu) using Apache Tomcat, ensuring high availability and stability.
    • Implemented LDAP-based authentication and role-based access control, strengthening application security and access management.
    • Collaborated with cross-functional teams to support deployments, debug production issues, and improve backend system reliability.
    • Java 8
    • Spring Boot 2.3.4
    • PostgreSQL
    • Meghraj Cloud
    • LDAP
    • Tomcat
    • SVN
    • PuTTY
    • JIRA
  2. Mar 2023 — Oct 2024 1 yr 8 mos

    Software Engineer · Mind IT Systems, Delhi

    • Designed and developed scalable backend services using Java 19 & 21 and Spring Boot 3.2 within a microservices-based architecture.
    • Architected and maintained REST APIs supporting concurrent users, improving system performance and service scalability by 15%.
    • Implemented secure authentication using JWT and integrated AWS S3 for secure file storage and retrieval.
    • Optimized MySQL schemas, queries and transaction handling, reducing response time and improving data consistency.
    • Collaborated with frontend and QA teams to integrate APIs, resolve issues, and ensure end-to-end application stability.
    • Actively participated in Agile cycles — sprint planning, code reviews, and production deployments.
    • Java 19
    • Java 21
    • Spring Boot 3.2
    • Angular
    • AWS S3
    • MySQL
    • Git
    • Selenium
    • Tomcat (Ubuntu)
  3. May 2022 — Feb 2023 10 mos

    Full-Stack Developer Trainee · Cetpa Infotech Pvt, Noida

    • Collaborated with senior developers to build web applications using Java 8, Spring Boot, Angular, HTML and CSS during a comprehensive training program.
    • Developed RESTful APIs to facilitate efficient data exchange between frontend and backend systems.
    • Designed and optimized MySQL databases, improving query performance and data integrity.
    • Participated in code reviews, debugging and troubleshooting, contributing to high-quality software delivery.
    • Java 8
    • Spring Boot
    • Angular
    • MySQL
    • HTML
    • CSS

03 / Selected Work

Three systems worth explaining

Backend work has no screenshot. So here's the problem, the constraint, and the number that moved.

Ministry of Food Processing Industries Government of India

PM Formalisation of Micro Food Processing Enterprises (PMFME)

A national scheme portal generating heavy reports over high-volume transactional data. Report generation was slow and storage was growing faster than the budget for it.

  • Java 8
  • Spring Boot
  • PostgreSQL
  • Tomcat
  • Linux
  • Optimized backend APIs handling large datasets and report generation — reducing processing time by 50% and storage usage by 80%.
  • Designed and managed PostgreSQL schemas, indexes and relationships to support high-volume transactional data.
  • Developed and enhanced RESTful APIs using Java 8 and Spring Boot to support government-scale workflows and reporting.
  • Deployed and maintained applications on Linux-based servers using Apache Tomcat, ensuring stability and production readiness.

Impact — report generation pipeline

Processing time
before
−50%
Storage used
before
−80%

Achieved through API optimization over large datasets plus schema, index and relationship design in PostgreSQL.

Mind IT Systems

ESOP — Employee Stock Ownership Plan

Equity grant and vesting records are sensitive, auditable and document-heavy. The system needed hard authentication boundaries and fast document access without a distributed-systems tax.

  • Spring Boot
  • JWT
  • AWS S3
  • MySQL
  • Modular Monolith
  • Developed secure REST APIs within a modular monolithic architecture using Spring Boot and JWT-based authentication.
  • Integrated AWS S3 for document storage and retrieval, improving file access performance by 30%.
  • Optimized MySQL queries and transaction handling, reducing API response time by 20%.
  • Collaborated with cross-functional teams to integrate backend services and ensure data consistency across modules.

Trade-off

A modular monolith over microservices — deliberately. Grant, vesting and document modules share one transactional boundary, so consistency comes free from the database instead of being reimplemented in application code. The cost is coupled deployment; the benefit is that equity records can't drift.

Auth flow — JWT + S3 document fetch

GET /api/v1/grants/{id}/documents
Authorization: Bearer <jwt>
Accept: application/json
200 OK
{
  "grantId": "GR-2024-0117",
  "vested":  1250,
  "document": {
    "url": "<s3-presigned>",
    "ttl": 300
  }
}
401 Unauthorized
{
  "error": "token_expired",
  "message": "JWT has expired"
}

Illustrative of the API contract described above — presigned S3 URLs keep documents off the app server and out of the response payload.

Mind IT Systems

Mirai — Event Management System

Ticketing, check-in and media for live events, consumed by several client platforms at once. One backend, many front ends — so the API contract had to be the source of truth.

  • Spring Boot
  • AWS S3
  • AWS Rekognition
  • QR
  • Messaging
  • Designed and developed RESTful backend services using Spring Boot to support event management, ticketing and user interactions.
  • Implemented QR code generation and integrated messaging services for notifications and user engagement.
  • Utilized AWS S3 for media storage and Amazon Rekognition for image processing and indexing.
  • Ensured backend compatibility across multiple client platforms through well-defined API contracts.

Architecture

Web Client Mobile App Kiosk Spring Boot REST API one contract QR Generation Messaging AWS S3 · Media Rekognition Datastore indexes

Media lands in S3; Rekognition indexes it. Every client platform sees the same contract.

04 / Stack

What I build with

Grouped by how I actually use them — not by how confident a progress bar could pretend to be.

Languages

  • Java 8
  • Java 19
  • Java 21
  • SQL

Cloud & DevOps

  • AWS S3
  • AWS Rekognition
  • Tomcat
  • Ubuntu
  • Linux Deployment

Backend

  • Spring Boot
  • Hibernate
  • JPA
  • REST API Design
  • Microservices Architecture
  • PostgreSQL
  • MySQL
  • Apache Kafka
  • Docker
  • Maven
  • JWT Authentication
  • RBAC
  • System Design

Tools

  • IntelliJ IDEA
  • Spring Tool Suite
  • Eclipse
  • Postman
  • Git · GitHub
  • GitLab
  • JIRA
  • SVN
  • PuTTY
  • FileZilla
  • Jaspersoft

Frontend (secondary)

  • Angular
  • TypeScript
  • JavaScript
  • HTML
  • CSS
  • Bootstrap

05 / Education

Education

2021 — 2023

Master of Computer Applications

Ajay Kumar Garg Engineering College, Ghaziabad

Specialized in software development, algorithms and database systems.

2018 — 2021

Bachelor of Computer Applications

Dr. K.N. Modi Institute of Engineering & Technology, Modinagar

Focused on programming fundamentals, web development and computer applications.

2015 — 2018

High School & Intermediate

Kendriya Vidyalaya Mau & R.R.S IC Siswar

Foundational education with a focus on science and mathematics.

06 / Contact

Let's talk backend.

Open to backend engineering roles. The fastest way to reach me is email — I read everything.

codewithrohitsingh@gmail.com
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