Hi there! I'm Mostafijur Rahman, a passionate and detail-oriented Java developer with over 5 years of experience designing and developing scalable, efficient, and secure backend systems.

Currently, I’m working at Brain Station-23, specializing in developing Internet Banking systems and microservices-based platforms. My focus lies in real-time data processing, system optimization, and robust architecture design.

Languages: Java, Go
Frameworks: Spring Boot, Spring MVC, Spring Security, Spring Batch, Hibernate, JPA
Databases: PostgreSQL, Oracle, MySQL, Microsoft SQL Server
Messaging/Event Streaming: Apache Kafka
DevOps & CI/CD: Docker, Kubernetes, Jenkins, GitHub Actions
Security: OAuth2, JWT, Keycloak
Other: Quartz, Actor System, REST APIs, Agile practices, JasperReports

Brain Station-23 Ltd. | Dhaka, Bangladesh | 2020 – Present

At Brain Station-23, I’ve been working as a Java Backend Developer in the fintech domain, primarily focusing on building scalable and secure Internet Banking systems and enterprise-grade microservices platforms.

• NCC Always (NCC Bank)

  • Designed and developed core Internet Banking features including account management, fund transfers, and bill payments.
  • Implemented secure authentication and authorization mechanisms using Spring Security, OAuth2, and JWT.
  • Optimized PostgreSQL and Oracle queries to reduce transaction latency and improve performance.

• UNET Enterprise & Retail Banking (United Commercial Bank PLC)

  • Built and enhanced real-time payment services with Apache Kafka for an event-driven architecture.
  • Integrated Actor System with microservices to handle high-volume financial transactions reliably.
  • Developed bulk payment processing and corporate banking features, ensuring high scalability.
  • Resolved critical production issues, maintaining 99.9% uptime for banking services.

• City Optima Project

  • Developed backend services for subscription billing, account/card payments, and notification systems.
  • Implemented Quartz Scheduler for automated billing and recurring transactions.
  • Containerized microservices with Docker & Kubernetes, ensuring high availability and scalability.

• Micro Invoicing Solution – Enterprise Invoice Management System

  • Built a multi-tenant invoice management system with 15+ REST APIs using Spring Boot 3.4.5 and Java 21.
  • Implemented invoice lifecycle automation, quote-to-invoice conversion, and client/project tracking.
  • Integrated Keycloak (JWT) for role-based access and JasperReports for PDF generation with QR validation.
  • Delivered a scalable architecture reducing manual processing time for enterprise clients.

• Delivered clean, testable code with JUnit, Mockito, and WireMock.
• Reduced API response times by up to 30% in critical banking services through optimization.
• Actively contributed in Agile teams, participating in sprint planning, code reviews, and mentoring juniors.

🧠 Always eager to learn, solve complex problems, and contribute to impactful backend systems.

• Facebook: https://www.facebook.com/jmostafijur/
• Email: mostafijurj@gmail.com
• LinkedIn: https://www.linkedin.com/in/mostafijurj/
• Blog: https://mostafijurj.blogspot.com/
• Twitter: https://twitter.com/Kajol81302716