Vishal U.Private profile: Upwork shows its earnings only to signed-in members, so we check it every few weeks, not daily. MRR here is a rough estimate (Upwork's six-month earnings ÷ months active). Last read Nov 5, 2026.

Top Rated Plus Senior Java Developer (15+ YOE) specializing in Java Spring Boot, Microservices, REST APIs, Angular, and AS400 Migration. I architect enterprise-grade backend systems, full-stack web portals, and cloud-ready applications. I help businesses build new Spring Boot services, modernize existing Java applications, integrate frontend systems with backend APIs, and improve application reliability and maintainability. Operating as a hands-on Backend Developer, Backend Engineer, Java Architect, and Solution Architect, I combine 15+ years of engineering depth with modern AI tools like GitHub Copilot, Claude, and ChatGPT to accelerate delivery, improve code quality, and make architecture decisions that age well. Core Backend Development & Java Ecosystem: • Enterprise Java & Spring: I engineer high-concurrency backend applications using Core Java (OOP, Concurrency, Collections, Streams), Spring Boot, Spring Framework, Spring MVC, Spring Data JPA, Spring Security, Spring Batch, Spring Cloud, and Spring AOP. • API & Persistence Layer: I design scalable data access layers with Hibernate and JPA (Hibernate/JPA), alongside documented, versioned REST APIs, SOAP APIs (SOAPAPI), and GraphQL interfaces using Swagger and OpenAPI. • System Design & Domain Depth: I apply Clean Architecture, SOLID principles, Enterprise Architecture , and System Design to build High Availability and Fault Tolerant systems for Healthcare Java, Finance Java, ERP Java, and E-commerce platforms. Spring Boot Microservices & Event-Driven Architecture: • Microservices Transformation: I lead Monolith to Microservices initiatives utilizing service decomposition, API gateway patterns, service discovery, circuit breakers, distributed tracing, and fault tolerance. • Asynchronous Messaging: I build Event-Driven architectures and real-time message brokers using Apache Kafka, RabbitMQ, and ActiveMQ. Full-Stack Frontend Integration & Rapid MVP Delivery • Frontend Collaboration: Working as a Full Stack Developer, I integrate Angular, AngularJS, React (ReactJS), Vue.js, HTML5, CSS3, and JavaScript frontends with secure Java backend services. • POC & Startup MVP Execution: I deliver rapid POC Development and MVP Development for Startup MVP teams and enterprise innovators—shipping scalable architectures for fast iteration without accumulating technical debt. Legacy Modernization & AS400 / IBM i Migration: • RPG to Java Modernization: I specialize in Legacy Modernization and AS400 Migration (AS400Migration) across IBM i systems, executing RPG and RPGLE to Java migration with zero business disruption. • Database & Cutover Planning: I manage DB2 to modern database migration (DB2Migration), low-downtime cutover planning, and rollback-safe execution for legacy Java and IBM i environments. Cloud Migration, DevOps, Data & AI-Assisted Engineering • AWS, Azure & CI/CD: I lead Cloud Migration across AWS (EC2, ECS / AWSECS, S3, Lambda, ELB, Redshift, Cognito) and Azure (VMs, Blob Storage, AD, Data Factory), utilizing Docker containerization and CI/CD (CICD) pipelines via Jenkins, Maven, and GitHub Actions. • Databases, Search & ETL: I manage MySQL, PostgreSQL, Oracle, DB2, MongoDB, Elasticsearch (ELK Stack), and Redis, and build high-volume Spring Batch ETL data pipelines. • AI-Assisted Engineering: I integrate AI-Assisted Development using GitHub Copilot and Claude for intelligent code completion, refactoring, and architecture reviews, plus ChatGPT for rapid prototyping, test generation, and technical documentation. Whether you need a POC validated, an MVP shipped, a Java backend owned end-to-end, or a full AS400 modernization delivered safely—click "Hire Me" or send an invite and let's build something that scales.