Sajal Halder | Backend Engineer

About Me

ONLINE

about.json

{
  "name": "Sajal Halder",
  "role": "Software Engineer",
  "experience": "3+ years",
  "location": "Dhaka, Bangladesh",
  "specialization": [
    "Backend Development",
    "Microservices Architecture", 
    "System Design",
    "DevOps & Cloud Computing"
  ],
  "education": "B.Tech Computer Science Engineering",
  "university": "Lovely Professional University",
  "philosophy": "Detail-oriented engineer passionate about writing clean code and driving continuous improvement."
}

0

Daily API Transactions

0

Latency Reduction

0

Test Coverage

Technical Skills

Programming Languages

Java

Kotlin

C++

Dart

Python

SQL

Databases

MySQL

PostgreSQL

Mongodb

Redis

Apache Cassandra

Frameworks & Tools

Spring Boot

Microservices

JPA/Hibernate

JUnit 5

Gradle

Flutter

Kafka

DevOps & Monitoring

Docker

Kubernetes

Jenkins

SonarQube

Prometheus

Grafana

Professional Experience

Bangladesh Japan Information Technology Ltd.(BJIT)

Software Engineer

03/2023 – Present

Dhaka, Bangladesh

⚡ Developed microservices for Rakuten handling over 1 billion daily API transactions

🚀 Cut service latency by 28% using Java Virtual Threads for reactive backend optimization

🔧 Boosted CI pipeline reliability by 35% through improved testing strategies

📚 Created detailed API documentation, reducing onboarding time by 40%

Piyas International Ltd.

Software Engineer

04/2022 – 02/2023

Jashore, Bangladesh

🏗️ Built ERP system supporting 150+ active users with inventory and CRM modules

⏱️ Improved report generation speed by 90%, reducing execution time to under 1 minute

🔐 Designed secure APIs with RBAC and transaction-safe database interactions

Featured Projects

Rakuten BFF

Production

Backend for Rakuten supporting high-volume sessions. Delivered concurrent APIs managing 50K+ active sessions with near-zero latency.

Java Spring Boot Reactive Spring SonarQube

view details →

Rakuten Gateway

Live

Enhanced user search experience by aggregating responses from 5+ upstream services using Facade Design Pattern.

Java Spring Boot Microservices JUnit 5

view architecture →

ERP System

Completed

Built comprehensive ERP system supporting 150+ users with inventory and CRM modules. Improved report generation by 90%.

Java Spring Boot MySQL RBAC

case study →

Spring Boot QueryDSL API

Open Source

Developed a Spring Boot 3.4 REST API with dynamic querying capabilities using QueryDSL. Implemented a product catalog system with filtering, pagination, and sorting.

Java 21 Spring Boot 3.4 QueryDSL JPA

github repo →

URL Shortener Microservice

Open Source

Built a URL shortening service using microservices architecture. Features Docker containerization for easy deployment and scalability.

Java Microservices Docker Spring Boot

github repo →

Get In Touch

Let's build something amazing together. I'm always open to discussing new opportunities and interesting backend engineering projects.

@ newtonh48@gmail.com </> github.com/sajal48 in linkedin.com/in/sajal-halder48

contact.sh

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