Muthukumar K.

Senior Java Backend Developer

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Germany

Experience

Jan 2025 - Oct 2025
10 months

Senior Java Backend Developer

Upwork

  • Developed Java 21 / Spring Boot 3.2 microservices with REST and GraphQL APIs for GDPR-compliant consent workflows using Hexagonal Architecture
  • Enhanced Backend-for-Frontend (BFF) performance using AI-assisted tools for code refactoring and optimization
  • Built event-driven workflows with Kafka, RabbitMQ, AWS SQS, and integrated Salesforce Marketing Cloud for real-time consent tracking
  • Implemented OAuth2 and Keycloak security, automated CI/CD with Jenkins, GitHub Actions, and Gradle, and deployed containerized services on Docker and Kubernetes with AWS and Azure
  • Executed unit, integration, and contract testing with JUnit 5, TestNG, Mockito, and TestContainers; monitored performance via Grafana, Kibana, and AWS CloudWatch
  • Developed microservices for digital identity verification and e-signature management with Hexagonal Architecture
  • Integrated Keycloak 24.x with OAuth2.1 and OpenID Connect for SSO and RBAC, ensuring EU eIDAS compliance
  • Designed API-first microservices with OpenAPI 3.1, Swagger, and GraphQL for improved interoperability
  • Automated CI/CD pipelines with Jenkins, GitHub Actions, and Gradle; deployed containerized services on AWS EKS and Azure; monitored with Grafana, Kibana, CloudWatch, and TestContainers
Sep 2023 - Dec 2024
1 year 4 months

Senior Java Developer

Accenture

  • Developed Java 21 / Spring Boot 3.1 microservices for quoting, claims, and policy renewals using Hexagonal Architecture and DDD
  • Implemented asynchronous event-driven workflows with Apache Kafka 3.6, RabbitMQ, and ActiveMQ
  • Integrated GraphQL APIs with REST endpoints and applied AI-assisted tools for refactoring and optimization
  • Utilized gRPC v1.56 for high-performance inter-service communication, reducing latency by 20%
  • Managed data persistence with MongoDB, Couchbase, Redis, and PostgreSQL
  • Secured backend APIs using OAuth2.1, Keycloak 24.x, and JWT for SSO and RBAC
  • Automated CI/CD with Jenkins, GitHub Actions, and Gradle; containerized deployments on Docker and Kubernetes (AWS EKS/ECS, Azure)
  • Integrated Salesforce middleware and Shopify APIs to synchronize policy and quote data
  • Configured Grafana, Kibana, and AWS CloudWatch dashboards; used TestContainers for integration testing
May 2023 - Sep 2023
5 months

Senior Java Developer

Engineering Group

  • Developed Java 17 / Spring Boot 2.6 microservices for account and payment processing using Hexagonal Architecture
  • Integrated REST and GraphQL APIs and applied AI-assisted tools for code refactoring and performance optimization
  • Implemented asynchronous workflows with Kafka 2.8 and ActiveMQ 5.16 for real-time transaction updates
  • Managed Oracle 19c and PostgreSQL 13 databases with Spring Data JPA and Flyway
  • Automated CI/CD pipelines with Jenkins and GitHub Actions; containerized microservices with Docker and deployed on AWS EKS/Kubernetes
  • Secured APIs with Keycloak, OAuth2.1, and JWT for federated SSO and RBAC
  • Configured Grafana, Kibana, Prometheus, and AWS CloudWatch for monitoring and anomaly detection; used TestContainers for integration testing
  • Applied JVM optimization techniques and multithreading strategies to enhance performance
  • Integrated Salesforce APIs for customer data synchronization
  • Ensured observability, resilience, and scalability of distributed systems
Jul 2021 - Feb 2023
1 year 8 months

Senior Java Developer

IASON

  • Developed Java 12 / Spring Boot 2.2 microservices for employee and inventory management, integrating REST APIs and applying AI-assisted code optimization tools
  • Implemented asynchronous workflows with Apache Camel 3.x, Kafka 3.6, RabbitMQ 3.9, and ActiveMQ 5.x
  • Secured services with Spring Security, OAuth2.0, Keycloak, and JWT for role-based access control and compliance
  • Automated CI/CD pipelines with Jenkins, GitHub Actions, and Gradle; containerized deployments on Docker (AWS EKS/ECS, Azure)
  • Enhanced observability and performance with Grafana, Kibana, AWS CloudWatch, and TestContainers
Jan 2020 - Jul 2021
1 year 7 months

Java Developer

Reply Srl

  • Developed modular microservices for employee and inventory management using Java 12 and Spring Boot 2.2
  • Secured APIs and services with Spring Security, OAuth2.0, HTTPS, and RBAC
  • Implemented asynchronous, event-driven processing with Apache Camel 3.x, Kafka 3.6, RabbitMQ 3.9, and ActiveMQ 5.x
  • Containerized microservices with Docker and deployed on AWS EKS/ECS; leveraged AWS Secrets Manager for secure credential management
  • Automated CI/CD pipelines with Jenkins and Maven; integrated JUnit 5 and Mockito for testing
  • Maintained observability with AWS CloudWatch, Grafana, and Kibana
  • Developed backend billing and accounting microservices using Java 11, Spring Boot 2.0, and Spring MVC with REST and GraphQL APIs
  • Implemented OAuth2.0, Keycloak, and JWT for secure authentication
  • Designed multi-threaded and event-driven workflows with Kafka 3.5 and ActiveMQ 5.x
  • Automated build and deployment with Jenkins, Maven, and GitHub Actions; containerized services on Docker and Kubernetes
  • Enhanced performance with Redis caching and hybrid data storage using MongoDB and Couchbase
  • Converted an iText-based PDF signing web application to ASP.NET, handling API calls, key exchange, hashing, and PDF processing with RUPS, pdfSweep, and pdfHTML
  • Refactored legacy code and implemented PBE with MD5 and DES algorithms for encryption and decryption
Mar 2017 - Oct 2019
2 years 8 months

Java Automation Tester

Inetz Tech Solutions

  • Selected test cases for automation and performed functional testing of the front-end using Selenium IDE and WebDriver
  • Created a data-driven framework using TestNG
  • Conducted parallel browser testing using Selenium Grid
  • Developed the persistence layer using Hibernate ORM with HQL and Criteria API
May 2014 - Jun 2015
1 year 2 months

Web Developer

Infiniti Software Solutions Pvt. Ltd

  • Developed a travel automation platform to provide backend support to travel agencies
  • Integrated multiple GDS/APIs and accounting systems into the online booking tool to automate processes
  • Implemented the MVC framework and front-end development using HTML, CSS, Bootstrap, JavaScript, and jQuery
  • Integrated databases with MySQL, PostgreSQL, and MongoDB
Dec 2011 - Sep 2012
10 months

Software Application Developer

Apollo Computer Education

  • Developed a MATLAB-based educational project
  • Integrated system projects utilizing microcontrollers, Raspberry Pi, and Embedded C

Summary

Senior Java Backend Developer with 8+ years of experience in designing and developing scalable microservices using Java 8-21 and Spring Boot. Skilled in Hexagonal Architecture, DDD, REST/GraphQL APIs, and event-driven systems with Kafka, RabbitMQ, and Apache Camel. Experienced in secure authentication (OAuth2.1, OpenID Connect, Keycloak), CI/CD automation (Jenkins, GitHub Actions, Maven, Gradle), and containerized deployments on Docker, Kubernetes, AWS, and Azure. Proficient in cloud integrations, AI-assisted code optimization, and middleware (Salesforce, Shopify), ensuring high performance, reliability, and observability across distributed systems.

Skills

  • Backend & Frameworks: Java 8-21, Spring Boot 2.x-3.x, Spring Mvc, Spring Data Jpa, Spring Security, Spring Cloud, Rest/graphql Apis, Openapi/swagger, Microservices, Hexagonal Architecture, Ddd, Grpc, Soap
  • Messaging & Event Systems: Apache Kafka, Rabbitmq, Activemq, Apache Camel, Event-driven & Asynchronous Processing
  • Databases & Storage: Postgresql, Mysql, Oracle, Mongodb, Couchbase, Redis, Hibernate Orm, Flyway, Liquibase
  • Cloud & Devops: Aws (Eks/ecs, Lambda, S3, Rds, Cloudwatch, Secrets Manager), Azure, Gcp, Docker, Kubernetes, Terraform, Helm, Ci/cd (Jenkins, Github Actions), Sonarqube
  • Integration & Middleware: Salesforce Api, Shopify Api, Api Gateway, Webhooks, Custom Integrations
  • Testing & Qa: Junit 5, Mockito, Testng, Postman, Wiremock, Testcontainers, Contract & Performance Testing
  • Monitoring & Observability: Grafana, Kibana, Prometheus, Elk Stack, Aws Cloudwatch, Zipkin, Jaeger
  • Security & Authentication: Oauth2.1, Openid Connect, Keycloak, Jwt, Sso, Rbac, Https/tls, Csrf Protection
  • Concurrency & Performance: Java Concurrency Api, Multithreading, Executor Framework, Reactive Streams, Jvm Performance Tuning

Languages

English
Native

Education

Jul 2015 - Sep 2016

VIT University

PhD by Research in Digital Communications · Digital Communications · Vellore, India

Aug 2012 - Apr 2014

Anna University

Master's Degree - Information Technology, IoT, Big Data Analytics and Cloud Computing · Information Technology · Chennai, India

Aug 2007 - Apr 2011

Anna University

Bachelor's Degree - Information Technology, Python Programming, Cloud Computing, IoT and C Programming · Information Technology · Chennai, India

Certifications & licenses

Driving Licence: B

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