08/04/2026 updated
100 % available
Senior Java Backend Developer
Hanoi, Vietnam
Only remote
B.Sc. in Computer ScienceAbout me
Senior Java Backend Developer with 8+ years building scalable systems using Spring Boot, microservices and Kafka. Experienced with AWS, Kubernetes, and high-traffic platforms. Available for remote freelance projects, open to short and long-term contracts.
Java (Programming Language)Spring SecurityDevOpsJava ArchitecturesJava Development ToolsSpring FrameworkJUnitPHP DevelopmentMockitoEvent-driven ArchitectureSpring CloudSpring BootBackendAWS ECSEvent Driven Architecture
Java & Spring Boot Development
Over 8 years of experience designing and implementing scalable, high-performance backend systems using Java (versions 8, 11, 17), Spring Boot, Spring Cloud, Spring Security, and Hibernate/JPA for enterprise applications.
Microservices & Cloud-Native Architecture
Deep expertise in microservices architecture, RESTful API design, Event-Driven Architecture, and Domain-Driven Design, combined with hands-on experience deploying on AWS (EC2, S3, Lambda) using Docker, Kubernetes, and GitLab CI/CD.
Messaging & Distributed Systems
Proven track record implementing event-driven solutions with Kafka and RabbitMQ, handling millions of daily transactions and improving system throughput significantly in distributed, high-availability environments.
Database Management
Solid experience with relational and NoSQL databases including PostgreSQL, MySQL, MongoDB, and Redis, including query optimization that reduced average response times from 800ms to 150ms.
DevOps & CI/CD
Hands-on experience with Docker, Kubernetes, Jenkins, and GitLab CI/CD pipelines, enabling efficient deployment workflows and reducing deployment times by up to 60%.
Testing & Quality Assurance
Proficiency in writing unit and integration tests using JUnit, Mockito, and TestContainers, achieving 85%+ code coverage in backend projects.
API Gateway & Migration
Experience leading migrations from monolithic APIs to Spring Cloud Gateway-based microservices architectures, reducing latency by 35% using Eureka, Docker, and AWS ECS.
Agile & Team Leadership
Experience leading technical teams in Agile/Scrum environments, conducting code reviews, architecture design sessions, and mentoring junior developers.
Build & Project Management Tools
Proficiency with Maven and Gradle for build automation, as well as Git for version control and system design practices in enterprise-level projects.
Over 8 years of experience designing and implementing scalable, high-performance backend systems using Java (versions 8, 11, 17), Spring Boot, Spring Cloud, Spring Security, and Hibernate/JPA for enterprise applications.
Microservices & Cloud-Native Architecture
Deep expertise in microservices architecture, RESTful API design, Event-Driven Architecture, and Domain-Driven Design, combined with hands-on experience deploying on AWS (EC2, S3, Lambda) using Docker, Kubernetes, and GitLab CI/CD.
Messaging & Distributed Systems
Proven track record implementing event-driven solutions with Kafka and RabbitMQ, handling millions of daily transactions and improving system throughput significantly in distributed, high-availability environments.
Database Management
Solid experience with relational and NoSQL databases including PostgreSQL, MySQL, MongoDB, and Redis, including query optimization that reduced average response times from 800ms to 150ms.
DevOps & CI/CD
Hands-on experience with Docker, Kubernetes, Jenkins, and GitLab CI/CD pipelines, enabling efficient deployment workflows and reducing deployment times by up to 60%.
Testing & Quality Assurance
Proficiency in writing unit and integration tests using JUnit, Mockito, and TestContainers, achieving 85%+ code coverage in backend projects.
API Gateway & Migration
Experience leading migrations from monolithic APIs to Spring Cloud Gateway-based microservices architectures, reducing latency by 35% using Eureka, Docker, and AWS ECS.
Agile & Team Leadership
Experience leading technical teams in Agile/Scrum environments, conducting code reviews, architecture design sessions, and mentoring junior developers.
Build & Project Management Tools
Proficiency with Maven and Gradle for build automation, as well as Git for version control and system design practices in enterprise-level projects.
Experience
Professional experience5 - 10 years
Freelancer since2023
Languages
EnglishFluent
Project history
Designed and developed microservices handling 2M+ daily transactions. Led migration from monolith to microservices architecture, reducing deployment time by 60%. Implemented event-driven architecture using Kafka, improving system throughput by 40%. Mentored 4 junior developers and conducted code reviews and architecture design sessions. Tech stack: Java 17, Spring Boot, Kafka, PostgreSQL, Docker, Kubernetes, AWS.
Architected a fault-tolerant payment system using event sourcing and CQRS, handling 1M+ transactions/day with 99.99% uptime. Tech: Java, Spring Cloud, Kafka, PostgreSQL, Kubernetes.
Built a real-time inventory sync system across multiple warehouses using WebSocket and Redis pub/sub, reducing stock discrepancies by 90%. Tech: Spring Boot, Redis, WebSocket, MongoDB.