13+ years experienced in Java/J2EE | AWS Certified(SAA , DVA, CloudOps) | Java Professional Certified | Docker | Kubernetes | Rest API | OPENAPI| Spring boot| JPA | Oracle | Mysql | Process Mining | AI | Langchain | Langgraph | RAG | MCP | OpenAI | React Js| ZK | EJB Certified | 7 years in Financial or Banking application | Agile/Scrum | Lead Team.

I am a Senior Backend Java Developer with 16+ years of hands-on experience architecting and delivering high-performance, scalable enterprise systems. I specialize in Spring Boot microservices, RESTful API development, and database optimization - consistently delivering bug-free, production-ready code on time. I have successfully built and maintained backend systems across Banking & Finance, eCommerce, Purchase & Procurement, and Legal domains - giving me a deep understanding of business-critical requirements and compliance-sensitive environments. If you need a reliable, senior-level Java developer who treats your project like a long-term investment - not just a task - I am the right partner. What I Deliver: Spring Boot Microservices : scalable, maintainable service architecture RESTful API Development : secure, well-documented, production-grade APIs Database Design & Optimization : PostgreSQL, MySQL, JPA, Hibernate, JooQ Legacy System Modernization : migrate monoliths to modern microservices CI/CD Pipeline Setup : GitLab, Docker, automated testing & deployment Backend Integration : third-party APIs, payment gateways, middleware Performance Optimization : query tuning, bottleneck resolution Code Review & Refactoring : clean code, SOLID principles Technical Skills: Backend & Frameworks : Java (16+ years), Spring Boot (6+ years), Spring MVC (5 years), Struts (3 years), Swing (3 years) API & Security : RESTful API Design, JWT, Keycloak, Swagger / OpenAPI, Postman Databases : PostgreSQL (5+ years), MySQL (3 years), JPA / Hibernate (3 years), JooQ (1+ year) DevOps & CI/CD : Docker (2+ years), GitLab CI/CD (2 years), Git (6+ years), Linux / Ubuntu (3 years) Testing & Quality : JUnit (5+ years), TDD, Test Containers, Integration & Unit Testing, Postman Test, Selenium, Playwright Reporting & Tools : Jasper Reports (3 years), Maven / Gradle (6+ years), Jira (5+ years), Eclipse, NetBeans, JSoup, PDFBox Frontend Support : Thymeleaf, ZK Framework, Responsive Web Applications Domain Experience : Banking & Finance, eCommerce, Purchase & Procurement, Legal. 16+ years of proven, real-world enterprise experience Bug-free delivery through rigorous TDD and quality assurance On-time, milestone-driven project execution Clear, responsive, and professional communication Full project lifecycle coverage - from requirements to post-delivery support Enterprise-grade, clean, and maintainable code every time

✅ 8+ Years of Java Development Experience ⚡ Full-Cycle Backend Development & Architecture ⚡ AI-Powered Development for Faster Delivery & Better Code Quality 👀 Click Invite or Hire for Scalable Java Backend Solutions Looking for a Java Developer who can build scalable backend systems, SaaS platforms, enterprise applications, and cloud-native solutions designed for long-term growth? For 8+ years, I have helped startups, SaaS companies, fintech businesses, AdTech platforms, and enterprise organizations build secure, scalable, and high-performance software using Java, Spring Boot, PostgreSQL, MySQL, Kafka, GraphQL, AWS, Docker, Kubernetes, and modern cloud technologies. From backend architecture and microservices development to legacy application modernization, API integrations, troubleshooting, cloud deployments, and AI-assisted engineering, I deliver production-ready solutions built to scale. 👉 WHAT YOU GET: ✔️ Java Backend Development & Software Architecture ✔️ Spring Boot Applications & Microservices ✔️ REST APIs, GraphQL APIs & Integrations ✔️ Cloud-Native Applications using AWS ✔️ AI-Assisted Development & Automation ✔️ Legacy System Modernization ✔️ Long-Term Support, Maintenance & Optimization 🏆 KEY ACHIEVEMENTS: ✔️ 8+ years building Java, Spring Boot, and enterprise backend applications ✔️ Built scalable SaaS platforms, fintech applications, AdTech systems, and enterprise software ✔️ Maintained and enhanced 15+ production microservices ✔️ Contributed to Adstrome, TrustArc, Acquia DAM, and Digi-Docket ✔️ Designed secure APIs, event-driven systems, and scalable architectures ✔️ Improved application performance through optimization and modernization ⚙️ CORE EXPERTISE: ✔️ Java, Core Java, Java EE, Spring Boot, Spring MVC, Spring Security ✔️ Hibernate, JPA, JDBC, MyBatis, ORM Frameworks, REST APIs, GraphQL APIs ✔️ Microservices Architecture, Apache Kafka, Event-Driven Systems ✔️ PostgreSQL, MySQL, Snowflake, Query Optimization ✔️ AWS, Docker, Kubernetes, Jenkins, Maven, Gradle, Git, GitHub, Bitbucket, Version Control Systems ✔️ Authentication, Authorization, RBAC, Multi-Tenant SaaS ✔️ ZK Framework & Enterprise Web Application Development 🛠 DEVELOPMENT & MAINTENANCE: ✔️ Web Application Development & Enterprise Software Development ✔️ Spring MVC & ZK Framework Application Development ✔️ Legacy Application Maintenance, Modernization & Application Upgrades ✔️ Feature Development & Application Enhancements ✔️ Bug Fixing, Root Cause Analysis & Production Support ✔️ Performance Bottleneck Analysis & Optimization ✔️ Memory Leak Detection & Resolution ✔️ Security Vulnerability & CVE Remediation ✔️ Third-Party API Integration & Business Workflow Automation ✔️ Performance Optimization & Scalability Improvements ☁️ CLOUD & DEVOPS: ✔️ AWS Cloud Services, Docker Containerization & Containerized Application Deployment ✔️ Kubernetes Container Orchestration for Scalable Cloud Infrastructure ✔️ Linux-Based Server Systems, Linux Server Administration & Linux Server Troubleshooting ✔️ Apache Tomcat Installation, Deployment, Monitoring & Performance Tuning ✔️ CI/CD Pipelines, Jenkins Automation, Git, GitHub, Bitbucket & Version Control Systems ✔️ Web Application Troubleshooting, Production Environment Support & Incident Resolution 🧪 TESTING & QUALITY: ✔️ JUnit, Mockito, Unit Testing & Integration Testing ✔️ Test-Driven Development & Automated Testing ✔️ API Testing, Debugging & Log Analysis ✔️ Root Cause Investigation & Production Stability ✔️ Code Quality Improvements & Maintainable Software Development ✔️ Regression Testing & Application Reliability Improvements 🤖 AI-ENHANCED ENGINEERING: ✔️ AI-Assisted Development & AI-Powered Coding Workflows ✔️ OpenAI API Integration, LLM Workflows & AI Automation ✔️ AI-Assisted Testing, Refactoring & Documentation ✔️ Faster Delivery Through AI-Enhanced Engineering 🏢 INDUSTRY EXPERIENCE: ✔️ SaaS Platforms & Enterprise Applications ✔️ AdTech & Programmatic Advertising ✔️ Fintech & Loan Processing ✔️ Privacy & Compliance Systems ✔️ Digital Asset Management ✔️ Multi-Tenant & White-Label Solutions 🚀 WHY CLIENTS CHOOSE ME: ✔️ 8+ Years of Java Development Experience ✔️ Enterprise SaaS & Microservices Expertise ✔️ Strong Spring Boot & Cloud-Native Skills ✔️ Scalable, Secure & Maintainable Solutions Whether you need to build a backend platform from scratch, scale an existing SaaS application, maintain a legacy system, resolve performance bottlenecks, remediate security vulnerabilities, implement microservices, modernize enterprise software, deploy applications on Tomcat or Linux-based server systems, integrate AI capabilities, or optimize application performance, I can help. Looking for a Java Developer, Senior Java Developer, Java Backend Developer, Spring Boot Developer, Java Architect, Backend Engineer, Enterprise Software Developer, API Developer, GraphQL Developer, AWS Developer, Cloud Engineer, Kafka Developer, Software Architect, Backend Architect, or Java Consultant?

Over the last 10+ years, I have developed a wide range of Enterprise Web Applications using Java. My Skills include : ✅ Java, JavaEE, EJB, JSP, Servlet, Hibernate, JPA, Android ✅ Frameworks: Grails with Groovy, Spring MVC, JSF, Struts, GAE, ZK, Android SDK ✅ Cloud services : AWS (EC2, RDS, Elastic Beanstalk, S3), Google Services ✅ Databases: MySql, MSSQL, Oracle ✅ Reporting Tools: iText, Apache POI, JasperReport, Aspose, Highcharts ✅ JAX-RS, REST API, Web Service, XML, JSON, Amazon S3/EC2 Services ✅ Web Security (XSS Attack, SQL Injection, XSRF Attack, Server Security) ✅ Social Integration : Facebook, Twitter, YouTube, Google+ Integration ✅ Payment Gateway : Payeezy(FirstData), Stripe, Twillo ✅ Frontend Tools: HTML, JavaScirpt, jQuery, Ajax, CSS, Bootstrap ✅ VCS: GIT, SVN ✅ Build Tools: Maven, Ant, Gradle ✅ Server: Tomcat, NGINX, JBoss (WildFly) ✅ IDE: Eclipse, Intellij, NetBeans, Android Studio ✅ Unit Test: JUnit, Mockito ✅ Automation: Selenium web driver I believe in quality along with deadline of the project.

🚀 Senior Back-End Engineer & Tech Leader (14+ yrs) — I help businesses build scalable, secure, and high-performance systems that handle millions of users and requests with ease. ✅ Delivered 50+ successful projects across healthcare, fintech, ed-tech, real estate, government, and non-profit sectors. ✅ Scaled apps from 1K → 1M+ daily requests and platforms from zero → 1M+ users. ✅ Trusted by global companies including Upwork (NASDAQ: UPWK), Letshego (Botswana Stock Exchange), OCO Global, and multiple startups worldwide. If you need a reliable partner who can architect solutions from scratch or optimize existing systems for performance, security, and scale — let’s talk. Do you like Upwork's Reports & Time tracking feature? I am one of those developers who built that :) ✅ How can I help you ✓ I can handle your all end-to-end requirements analysis, UX, development, testing & delivery so you can focus on your sales & operations ✓ I can extend/develop your MPV product to production-ready ✓ I can develop products from scratch until the final delivery and support with maintained code quality and proper code coverage ✓ I can maintain your currently live products in the most optimum way by keeping quality and customer experience at first place in mind and with the minimum team and can save your cost ✓ I can choose the right technology stack and tools for your solution based on real needs and can save costs ✓ I can manage the team, do code reviews, handle CI/CD and releases, support live systems ✓ I can understand and implement the most difficult parts of software systems at very large-scale platforms like Upwork, (I am one of the Upwork platform devs) ✅ Expert areas - Java based back-end frameworks like Spring Modules (Spring MVC, Spring Security, Spring AOP, Spring Rest, Spring Data/JPA) & ZK (Zkoss) - ECMS implementation with Alfresco Content Services 4.x, 5.x, 6.x and Alfresco Process Services (Activiti) - RDBMS (MySQL, PostgreSQL, Oracle) - Graph/Document Databases MongoDB and DynamoDB - Web Crawlers with all features - Microservices based architecture implementation with Spring boot, Spring Integration and Apache Camel - AWS experience with RDS, SQS, SNS, SES, S3, and EC2 Instances - AWS API implementation experience - Queue based implementations with ActiveMQ/SQS - Test driven development implementation with unit and integration test cases with Junit/TestNG + Mockito + Spring - Database integration frameworks like JDBC/Hibernate/Sprint Data (ORM) and Spring Mongo - REST based Web Service/API implementation with Spring REST - CI/CD implementation with (Bamboo + Jenkins + Maven + Nexus + GIT(Bitbucket/Gitlab/Github)) - Payment Gateways implementations like Paypal and Stripe with debit/credit card integration - Solr/Lucene/ElasticSearch search engine integration - Jasper Reports (with DynamicJasper as well) - Agile Methodology understanding all terminology - Experience with implementing very complex queries with MySQL db - Java based Servers Tomcat/JBoss - Repositories like Git, SVN, P4V(Perforce) ✅ What my clients says (You may check in Work History) ⭐⭐⭐⭐⭐ "Vishal is best developer I have worked with till date. He is prompt responsive, an incredible problem solver, very professional, highly skilled and great team leader. He handles our portal continuous development including all project phases starting from requirement gathering(calls), task creation with all details, estimation, development, deployment on all environments, testing, creating wiki pages, choose right technology stack and AWS resources and manage tickets! He is handling dev team and also do development himself and supports everyone. Will certainly work with him again when we restart the project development! Highly recommended developer." 👤 Hugo Galicia ( CEO @ chicagodealvault.com ) ⭐⭐⭐⭐⭐ "It was a highly positive experience working with Vishal. He was conscientious, always doing his due diligence to clarify any uncertainties before starting work. He gives accurate estimates of effort/time required for work, and either delivers on time or early. Overall a very reliable and dependable worker. We hope to work together with him soon. Highly recommended!" 👤 Dominik Bieringer ( CEO @ Kandu ) ⭐⭐⭐⭐⭐ "Very experienced and diligent contractor" 👤 Abhijit Dhar ( VP - Technical Services @ Whitehat Virtual Technologies ) ⭐⭐⭐⭐⭐ "Vishal is an excellent java engineer, with great business logic, self-motivated, with deep technical knowledge. He jumped right in and understood the current project architecture with minimum KT and limited documentation. He is always eager to solve new issues. I highly recommend him and will definitely work with him again, if opportunity permits. A pleasure to work with" 👤 Chris Adams ( CEO @ eDataSource )

🌟 Top Rated Plus & Expert-Vetted Freelancer on Upwork 🌟 I’m a seasoned Software Engineer with 12+ years of experience in building high-performance, enterprise-grade applications and cloud-native platforms. I specialize in developing scalable multi-tenant SaaS products, AI-powered automation tools, and secure, cloud-based backend systems. I have led the end-to-end development of enterprise SaaS platforms used globally, with a focus on microservices architecture, event-driven design, and robust multi-region tenant isolation. My experience also extends to integrating advanced AI workflows into production systems using cutting-edge tools like OpenAI and Google Vertex AI. I bring a results-driven mindset, strong problem-solving ability, and the ability to align technology with business goals. Whether you need to build from scratch, modernize an existing system, or integrate AI, I can help deliver value quickly and reliably. 💼 Core Expertise • SaaS Architecture: Multi-tenant design, tenant-aware microservices, RBAC, region-based deployments • AI Integrations: OpenAI (GPT), Google Vertex AI, LangChain, Pinecone, embeddings, vector search, LLM agents • Cloud & DevOps: AWS (Lambda, ECS, RDS, Cognito), GCP (Cloud Functions, Cloud Run, BigQuery), Docker, Kubernetes, Terraform • Backend Development: Java (Spring Boot), Python (FastAPI, Django), Node.js (Express, NestJS), PHP (Laravel) • Frontend Development: React, Angular, Vue.js, Tailwind CSS • CI/CD & Monitoring: GitHub Actions, Jenkins, AWS CodePipeline, Prometheus, Grafana, ELK, CloudWatch • Databases & Caching: PostgreSQL, MySQL, MongoDB, DynamoDB, Redis If you’re looking for a developer who can take ownership, move fast, and deliver production-ready results, let’s connect. I’m confident I can help you build reliable software that scales with your business.

With over 24 years of expertise in Progress OpenEdge database administration and Java/OpenEdge development, I bring a wealth of experience to the table. My skills extend beyond traditional database administration into the realms of software development and architecture. As a seasoned Progress/OpenEdge/Java Developer and OpenEdge Database Administrator, I excel at optimizing database performance, ensuring data integrity, and leading complex projects to success. My commitment to delivering high-quality solutions is unwavering, and I have a proven track record of achieving exceptional results. I am passionate about leveraging my extensive knowledge to drive database management and software development excellence. Key Skills: 🚀 Programming Languages: Proficient in Progress OpenEdge 9.X, 10.X, 11.X, 12.X 4GL/ABL, Java, Android, HTML, and JavaScript. 🛠️ Frameworks: Experienced in OpenEdge ABL, ADM2, Spring, Struts, JPA, Hibernate, and ZK. 💾 Databases: Well-versed in OpenEdge, MySQL, PostgreSQL, and Oracle. 🌐 Middleware: Skilled in managing middleware technologies such as Tomcat, JBoss, Apache HTTP Server, NGINX, OpenEdge Classic AppServer, PASOE, Webspeed, REST API, SonicMQ, JMS Adapter, and ActiveMQ. 🛠️ Tools: Proficient in Eclipse, OpenEdge Developer Studio, PCT, SVN, ANT, Maven, and Jenkins. 🖥️ Operating Systems: Experienced in Windows, IBM AIX, Linux, and HP-UX. I am eager to collaborate on challenging projects within dynamic organizations that value expertise and innovation in both database administration and software development. Let's work together to drive your projects to success.

Looking for a developer who can own your project end-to-end, deliver clean architecture, write scalable code, and communicate clearly? That’s exactly what I do. I’m a Senior Full-Stack Java Developer with 10+ years of experience building robust, secure, and enterprise-grade SaaS platforms using: 💻 𝐁𝐚𝐜𝐤𝐞𝐧𝐝 𝐄𝐱𝐩𝐞𝐫𝐭𝐢𝐬𝐞 - Java (8–25), Spring Boot, Spring MVC, Spring Security - Microservices architecture - REST APIs & GraphQL - JPA/Hibernate & JDBC - Maven/Gradle - Redis, Kafka, RabbitMQ - Unit & Integration Testing (JUnit, Mockito) 🌐 𝐅𝐫𝐨𝐧𝐭𝐞𝐧𝐝 𝐄𝐱𝐩𝐞𝐫𝐭𝐢𝐬𝐞 - Angular, React, TypeScript - HTML5, CSS3, Tailwind - Responsive UI, component-based architecture 🗄️ 𝐃𝐚𝐭𝐚𝐛𝐚𝐬𝐞𝐬 - PostgreSQL • MySQL • SQL Server • MongoDB • Cloud SQL • Datastore ☁️ 𝐃𝐞𝐯𝐎𝐩𝐬 / 𝐂𝐥𝐨𝐮𝐝 - Docker, Kubernetes, CI/CD - AWS (EC2, RDS, S3, Lambda) - GCP & Azure --------------------------------------------------------------------------------------------------------------------- ⭐ 𝐖𝐡𝐚𝐭 𝐈 𝐂𝐚𝐧 𝐃𝐨 𝐟𝐨𝐫 𝐘𝐨𝐮 I help companies build: ✔ SaaS platforms (CRM, HRM, ERP, dashboards, portals) ✔ Secure, high-volume web apps with clean APIs ✔ Enterprise microservices running at scale ✔ Complete MVPs from scratch ✔ System modernization (Monolith → Microservices) ✔ Admin panels, reporting, workflow automation ✔ Integrations with Stripe, PayPal, Twilio, SendGrid, etc. --------------------------------------------------------------------------------------------------------------------- 💡 𝐖𝐡𝐲 𝐂𝐥𝐢𝐞𝐧𝐭𝐬 𝐇𝐢𝐫𝐞 𝐌𝐞 - Strong architectural thinking - Clean, maintainable code - On-time delivery - Excellent communication - Ability to work independently - Flexible to work with Team - Flexible with time zones - End-to-end ownership (idea → deployment → maintenance) --------------------------------------------------------------------------------------------------------------------- 🔧 𝐓𝐨𝐨𝐥𝐬 & 𝐓𝐞𝐜𝐡𝐧𝐨𝐥𝐨𝐠𝐢𝐞𝐬 - IntelliJ IDEA • Git • Jira • Docker • Kubernetes • Jenkins • Postman • Swagger --------------------------------------------------------------------------------------------------------------------- 🧩 𝐋𝐞𝐭’𝐬 𝐁𝐮𝐢𝐥𝐝 𝐒𝐨𝐦𝐞𝐭𝐡𝐢𝐧𝐠 𝐆𝐫𝐞𝐚𝐭 Whether you need a backend expert, a full-stack developer, or someone to architect your entire SaaS, I’d love to help.

I'm java expert over 15 years in many positions such as as programmer, freelancer, analyst, java team leader, product architect, project manager. I'm major on Document Output, Document Management System, Enterprise Content Management (ECM), Document Conversion fields, Digital Image processing. Besides that, i have lot of experiences and good skills in WDK (Windows driver kit) development, Alfresco ECM, Filenet ECM, Filenet BPM, Education, Transportation, Hotel Reservation, Human Resource, Business Process Management (BMP), Groupon, CRM (Customer Relationship Management). About technology stack, almost time, I have worked and researched in J2EE technology and Open Source Frameworks such as Cruise Control, Hudson, JBoss, Apache Tomcat, Apache server, Tomcat/ JBoss High available system (HA- clustering & load balancing between many web servers), BPM Activiti, Apache Axis, Apache Struts, Apache Ant, Apache Lucene, Java Server Faces, ZK (the very famous Ajax framework for Java), Vaadin, GWT, Selenium, JQuery, iText, PDFLib, JTOpen, Spring, Hibernate, JPA, Eclipse, MyEclipse. Several years go, i started working with LAMP stack. MongoDB, Php, Wordpress, WooCommerce, Yii are also my favorite language/framework. My favorite methodology to develop software product is Test Driven Development (TDD). Generally, I’m very eager to work with Java and Php. In addition to the practical experience, I achieved the Master degree in Computer Science field at the Natural Science University with “Optical Music Recognition” in July 2005.

Hi everyone! I am an Oracle Certified full-stack Java developer with huge experience writing secure code. I have been working on banking software for one of our local banks in Ukraine for more than 9 years. And it’s not a single experience I have, also I have worked on eCommerce projects, and participated in the development of hiring platforms, and tools for the CA Gen environment. My main goal is to create long-term relationships with my clients and build qualitative and reliable applications. I like to learn new technologies and move on with the latest trends in IT industry. I am an easy-talk-to person and think that communication is important in the development field. Feel free to message me, I will be glad to answer all your questions! These are my key skills: Backend: Java 6+, JavaEE, JavaSE Spring (Spring boot, Spring JPA, Spring data, Spring security and other Spring modules) Hibernate SQL DBs (MySQL, Oracle, PostgreSQL, SQLite) Non SQL DBs (Redis, Mongo) Elastic (full-text search and complicated full-text search) Amazon S3, AWS Thymeleaf Jasper Report jBOSS JBPM JUnit Frontend: ZK Ajax JSP, PrimeFaces HTML, XML Groovy Angular React Others JavaFX Git, SVN Docker SDK Eclipse/IntelliJ Idea Have a nice day!