11/10/2026 updated
100 % available
Senior Java Backend Developer | Spring Boot, REST APIs & Relational Databases
Rotterdam, Netherlands
Only remote
Bachelor of Technology (B.Tech) in Computer ScienceAmazon Web ServicesCOBOL (Programming Language)MongoDBSQL and Java (SQLJ)KotlinApache Kafka
Java Backend Development & Microservices
Expertise in Java 8 to 17 (Core and Reactive), Spring Boot, Hibernate/JPA, and Microservices architecture. Extensive experience building high-performance, secure, and concurrent backend systems across Banking, FinTech, Retail, and Airline domains, including performance tuning and multithreading.
Relational & NoSQL Database Management
Strong proficiency in PostgreSQL and MySQL, including relational design, complex SQL query optimization, and schema tuning. Additional experience with MongoDB, Elasticsearch, and Redis for NoSQL and caching use cases.
Cloud, DevOps & CI/CD
Hands-on experience with CI/CD pipelines using Git, Jenkins, and Maven/Gradle. Proficient in containerization and orchestration with Docker and Kubernetes, cloud platforms including AWS (EC2, CloudWatch), GCP, and Pivotal Cloud Foundry (PCF), including blue-green deployment strategies.
Security & Authentication
Implementation of authentication and authorization controls using OAuth2 and JWT to secure REST APIs and microservices in high-stakes financial and retail environments.
Messaging & Event Streaming
Experience with Kafka for building producers and consumers to enable real-time inventory synchronization and event-driven communication across distributed systems.
Testing & Quality Assurance
Proficiency in JUnit and Mockito for unit and integration testing, as well as Postman for API testing, ensuring code quality and functional parity in complex migration projects.
Monitoring & Observability
Use of APM tools, DataDog, Kibana, and CloudWatch to build monitoring dashboards, set up alerting, and proactively resolve production incidents.
Enterprise Search & Coveo
Architecture and configuration of enterprise search strategies using Coveo, Microsoft Graph Connectors, SharePoint, and ServiceNow, including machine learning-based search relevance optimization.
Reactive Programming & Kotlin
Development of non-blocking, asynchronous APIs using Reactive Java (Project Reactor) and Kotlin for concise and safe query-formation logic, particularly in high-traffic retail environments.
Agile & Distributed Team Collaboration
Daily collaboration within Agile (Scrum/Kanban) teams across distributed locations, including sprint planning, stand-ups, retrospectives, and peer code reviews.
Expertise in Java 8 to 17 (Core and Reactive), Spring Boot, Hibernate/JPA, and Microservices architecture. Extensive experience building high-performance, secure, and concurrent backend systems across Banking, FinTech, Retail, and Airline domains, including performance tuning and multithreading.
Relational & NoSQL Database Management
Strong proficiency in PostgreSQL and MySQL, including relational design, complex SQL query optimization, and schema tuning. Additional experience with MongoDB, Elasticsearch, and Redis for NoSQL and caching use cases.
Cloud, DevOps & CI/CD
Hands-on experience with CI/CD pipelines using Git, Jenkins, and Maven/Gradle. Proficient in containerization and orchestration with Docker and Kubernetes, cloud platforms including AWS (EC2, CloudWatch), GCP, and Pivotal Cloud Foundry (PCF), including blue-green deployment strategies.
Security & Authentication
Implementation of authentication and authorization controls using OAuth2 and JWT to secure REST APIs and microservices in high-stakes financial and retail environments.
Messaging & Event Streaming
Experience with Kafka for building producers and consumers to enable real-time inventory synchronization and event-driven communication across distributed systems.
Testing & Quality Assurance
Proficiency in JUnit and Mockito for unit and integration testing, as well as Postman for API testing, ensuring code quality and functional parity in complex migration projects.
Monitoring & Observability
Use of APM tools, DataDog, Kibana, and CloudWatch to build monitoring dashboards, set up alerting, and proactively resolve production incidents.
Enterprise Search & Coveo
Architecture and configuration of enterprise search strategies using Coveo, Microsoft Graph Connectors, SharePoint, and ServiceNow, including machine learning-based search relevance optimization.
Reactive Programming & Kotlin
Development of non-blocking, asynchronous APIs using Reactive Java (Project Reactor) and Kotlin for concise and safe query-formation logic, particularly in high-traffic retail environments.
Agile & Distributed Team Collaboration
Daily collaboration within Agile (Scrum/Kanban) teams across distributed locations, including sprint planning, stand-ups, retrospectives, and peer code reviews.
Experience
Professional experience0 - 5 years
Freelancer since2026
Languages
EnglishFluent
Project history
Engineered high-concurrency Spring Boot microservices for core banking operations, ensuring thread safety and data integrity. Optimized complex SQL queries and database schemas, implemented OAuth2/JWT authentication, managed cloud deployments on PCF with blue-green strategies, and built monitoring dashboards using APM tools, resolving 100% of critical production incidents.
Architected an Elasticsearch-based cloud-deployed search strategy for the retail platform. Developed non-blocking asynchronous search APIs using Reactive Java, implemented Kafka producers and consumers for real-time inventory synchronization, and established real-time monitoring dashboards in DataDog and GCP.
Architected an enterprise search strategy to unify fragmented data across SharePoint, ServiceNow, and internal REST APIs. Configured Microsoft Graph Connectors for secure content indexing, utilized Coveo Machine Learning for search relevance optimization, and automated data indexing pipelines to reduce content searchability lag.