Available to hire
Hi, I’m Raj Kumaran, a Principal Full Stack Developer and Technical Leader with extensive experience delivering cloud-native transformations and modernizing complex systems. I specialize in Java, React, and cloud platforms (AWS and Azure), helping teams design scalable architectures with strong code quality.
I’m active in mentoring, pair programming, and AI-assisted development workflows, using tools like GitHub Copilot, Claude, OpenAI, and Ollama to speed up design decisions and boost delivery. I value collaboration, clean engineering practices, and continuous learning across the development lifecycle.
Skills
Experience Level
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Intermediate
Intermediate
Intermediate
Work Experience
Senior Java Developer at Travelers Insurance
November 1, 2024 - PresentSenior engineer building a scalable, event-driven insurance quote and pricing engine integrating underwriting, risk assessment, compliance, fraud detection, and collections services. Designed and implemented SpringBoot microservices handling real-time pricing and underwriting workflows. Engineered asynchronous processing pipelines with Apache Kafka to handle high-volume concurrent quote requests, optimizing premium calculation workflows and ensuring system performance under heavy load. Optimized system performance by implementing non-blocking messaging between pricing, risk, and fraud services to minimize latency, while tuning thread pools and JVM settings to support high-concurrency environments. Developed a centralized document management system using React and TypeScript, enabling seamless document lifecycle management with AWS S3 integration for secure upload/retrieval, built-in email functionality with attachment support, and real-time document tracking capabilities. Engaged in CI
Senior Java Developer at Nuffield Health
July 1, 2023 - November 1, 2024Developed high-throughput integration microservices for healthcare systems using HL7 protocols. Designed event-driven microservices to process concurrent patient data streams. Applied Domain-Driven and Event-Driven Architecture patterns. Implemented asynchronous messaging workflows using RabbitMQ and Kafka. Optimised throughput and reduced blocking operations in data exchange services. Conducted performance and scalability testing under concurrent loads. Performed code reviews emphasising thread-safety and reliability.
Senior Java Developer at Proximus Telecom
June 1, 2020 - June 1, 2023Developed scalable Identity & Access Management microservices with high concurrency requirements. Built high-throughput backend systems using Kotlin and reactive programming. Introduced distributed reactive patterns and multithreaded processing. Implemented real-time event streaming via Kafka. Applied concurrent collections and atomic operations in authentication and session services. Reduced latency in authentication workflows through non-blocking I/O. Developed React/TypeScript frontend features. Integrated CI/CD pipelines using Docker, Kubernetes, OpenShift.
Senior Java API Developer at Connectt Ltd
April 1, 2019 - May 1, 2020Senior backend developer within a team building and supporting a cloud-based, multi-tenanted SaaS platform handling high volumes of concurrent user activity. Shaped the application architecture using CQRS and microservices to ensure scalability and tenant isolation. Designed and implemented thread-safe REST APIs using Spring Boot to handle concurrent client requests efficiently. Refactored synchronous workflows into asynchronous messaging patterns using ActiveMQ to improve responsiveness and throughput. Leveraged Kotlin Coroutines and Flow to implement non-blocking background processing and concurrent data handling. Collaborated closely with frontend (Rect/TypeScript) and mobile teams to ensure efficient API design and low-latency interactions. Implemented secure authentication and authorisation using Spring Security, AWS Cognito, and JWT in a distributed environment.
Lead Java Developer at ESURE Group PLC
September 1, 2017 - March 1, 2019Led development of real-time pricing and underwriting engine integrating credit scoring and risk services. Architected event-driven pricing engine integrating NCD, Experian Credit Scoring, and underwriting tools. Designed concurrent service orchestration flows for premium calculations. Introduced Apache Camel and enterprise integration patterns. Monitored CPU, memory, and throughput using Dynatrace. Streamed logs to Elasticsearch and optimised system performance under load.
Senior Java Developer at Experian PLC
October 1, 2016 - August 1, 2017Implemented matching engine to find duplicate customers from RDBMS, NO-SQL, CSV and REST input. Gained extensive experience in normalization, standardization, blocking, scoring, clustering & output. Participated in analysing bottlenecks, memory leaks, CPU loads, and threading issues.
Senior Java Developer at Architects
March 1, 2016 - September 1, 2016Senior Java Developer: Implemented Charity Management System for Charity Commission using MuleSoft ESB; hosted in AWS; provided support.
Senior Java Developer at Verizon Ltd
June 1, 2015 - March 1, 2016Implemented the authentication and authorisation portal for the MOJ. Provided secure access to web applications via ForgeRock OpenAM and OpenDJ. Integrated identity providers like Barclays and Experian with GOV.UK/VERIFY services.
Lead Software Developer at Semafone Ltd
May 1, 2011 - June 1, 2015Designed and developed PCI DSS compliant payment system for Rogers Telecom, Canada. Integrated the SIP telephony application with a cluster of Java modules using ActiveMQ messaging broker. Implemented card payment processing, credit scoring, address verification, tokenising and de-tokenising.
Senior Software Engineer at Gamma Telecom
August 1, 2007 - May 1, 2011Implemented the Gamma Portal web application for provisioning services. Developed Number Management System for the telephone numbers and the added services.
Senior Software Engineer at MBIZ Global
October 1, 2006 - August 1, 2007Implemented automated billing solution for the try-and-buy games using PHP and MySQL.
Education
MSc in Computer Networks at University of Westminster
January 11, 2030 - March 23, 2026BSc in Computer Engineering at University of Moratuwa
January 11, 2030 - March 23, 2026Qualifications
MuleSoft Certified Developer – Integration and API Associate
January 11, 2030 - March 23, 2026Industry Experience
Financial Services, Healthcare, Telecommunications, Software & Internet, Professional Services
Skills
Experience Level
Expert
Expert
Expert
Expert
Expert
Expert
Expert
Intermediate
Intermediate
Intermediate
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