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I started his career as a programmer in Delphi, I work more than 15 years. There are also skills in C # (winforms) . (MSSQL, Oracle, MySQL, SQLite, PostgreSQL), also has skills with api functions, sound, theards etc. Working with REST API, like Elation, SureScript. Wrote simple backend server. Mobile develop on Delphi and Kotlin Compose. Have skill with https, ftps, sftp (etc) protocols.

I am a professional Ukraine based QA Specialist with more than 5 years of experience in software quality assurance, testing, validation, and verification. Well-versed in reviewing software requirement specifications, as well as identifying, creating, and implementing test scenarios, case, and scripts for various projects. I have 4+ years of experience in Automation QA, with a specific focus on using Selenium and BrowserStack for testing web applications. Over the years, I have developed proficiency in creating automated test scripts using Selenium and integrating them with BrowserStack for cross-browser testing. Additionally, I have a strong understanding of programming languages such as Java or Python, which has helped me in writing efficient and effective test scripts. - Extensive experience in Software testing, Web Application Testing, Product Testing and Data Entry. - Good experience in Mobile Application Testing on Android and iOS Platform. - Proficient in Black-box Testing, Functional Testing, Sanity testing, Integration Testing, System Testing, Usability Testing, GUI Testing, User Acceptance Testing (UAT) and Regression Testing. -Experience in Analyzing and designing Test cases, generating test scripts and analyzing test results, testing process, tracking and managing defects. -Experience in doing the Cross Browser testing on IE, FF, Safari, Netscape and Chrome. -Experience in creating Test Plan, Test Report, and Daily/Weekly Status Reports.​ - Extensive Experience in domains such as Core Banking, Investment Banking, Islamic Banking and Channel Testing. - Development automation scripts for mobile apps (iOS, Android) to test functionality, regression and sanity. - Development of automated test-suites using Selenium test suites, JUnit and TestNG.

⭐⭐⭐⭐⭐ Top Rated Plus on Upwork 100% Job Success Score I'm a Java developer with 8+ years delivering production-grade systems from serverless AWS architectures to distributed microservices serving healthcare and fintech clients. 𝗪𝗵𝗮𝘁 𝗜'𝘃𝗲 𝗕𝘂𝗶𝗹𝘁 ➡ As lead Java developer at my current company, managed a team of 8 engineers over 7 years — delivering 4 production systems across healthcare, fintech, and AI verticals. ➡ Designed serverless AWS infrastructure for a US longevity and healthcare platform as an AWS developer — Lambda, AppSync, DynamoDB, Cognito, SNS/SQS, Stripe, HubSpot currently in production. ➡ Led migration from monolithic Spring apps to distributed microservices — reducing deployment complexity and enabling independent scaling per service. ➡ Built a PDF/UA accessibility compliance platform as backend developer using Java 21, iText 7, PDFBox, veraPDF processing and remediating documents of hundreds of pages against international accessibility standards. ➡ Delivered an AI-powered workflow automation platform as an AI developer integrating Spring AI, Azure cloud, and automated Stripe subscription workflows. ➡ Shipped a medical practitioner dashboard integrating 3rd-party hardware APIs and clinical toolkits as backend developer and tech lead serving real patients and practitioners in production. Core experience as a Java developer and Backend developer As a Java developer with 8+ years in production systems, my core is Java 8 through Java 21 with the full Spring ecosystem Boot, Cloud, Security, WebFlux, Batch, and Spring AI for AI-integrated backends. I work across both relational (PostgreSQL, MySQL) and NoSQL (MongoDB, DynamoDB, Redis) databases, selecting the right store based on access patterns not habit. As a backend developer I've optimised slow MongoDB queries to cut response times, redesigned DynamoDB access patterns for a high-throughput healthcare API, and built Redis caching layers that kept latency flat under load. As an AWS developer, my hands-on stack covers Lambda, AppSync, DynamoDB, Cognito, SQS, SNS, SES, S3, API Gateway, Route 53, and CloudFormation built and maintained in a live US healthcare platform. I design serverless pipelines end-to-end, not just deploy to them. For async workloads I wire event-driven systems using Kafka, RabbitMQ, or AWS SNS/SQS depending on durability and throughput requirements. On the container side: Docker, Kubernetes, Helm, OpenShift, Terraform, and Jenkins full IaC from infrastructure definition to CI/CD pipeline. As an AI developer, I've shipped Spring AI integrations for workflow automation backends, built document intelligence services capable of processing and remediating hundreds-of-pages PDFs against accessibility standards, and connected GraphQL APIs via AWS AppSync for mobile and web AI-driven applications. I also have production experience integrating medical hardware APIs, Stripe subscription billing, and HubSpot CRM sync into Java backends the kind of third-party integration work every backend developer eventually owns in a real product. AWS Developer & 𝗖𝗹𝗼𝘂𝗱 𝗘𝗻𝗴𝗶𝗻𝗲𝗲𝗿𝗶𝗻𝗴 ✅ Currently operating as AWS developer on a live healthcare platform Lambda, AppSync, DynamoDB, Cognito, SQS/SNS/SES, S3, API Gateway, Route 53, CloudFormation ✅ Experience as AWS developer across serverless, containerized (ECS/K8s), and IaC (Terraform, CloudFormation) environments ✅ Also experienced across Azure (AKS, Azure DevOps) and GCP as multi-cloud backend developer ✅ Kubernetes, Helm, Docker, OpenShift, Jenkins, Terraform the full DevOps chain every AWS developer deploys through AI developer 𝗖𝗮𝗽𝗮𝗯𝗶𝗹𝗶𝘁𝗶𝗲𝘀 ✅ Delivered AI-powered backend services as AI developer using Spring AI automated content generation and workflow orchestration at scale ✅ AWS AppSync + DynamoDB + Cognito pipeline for a live healthcare platform: the architecture an AI developer builds when latency and data integrity are non-negotiable ✅ Experienced AI developer integrating third-party AI tooling with enterprise Java backends designing event-driven pipelines that handle async AI workloads via Kafka and SQS ✅ As AI developer, built document intelligence features automated PDF tagging, structure remediation, and accessibility validation across large document corpora 𝗜𝗻𝗱𝘂𝘀𝘁𝗿𝗶𝗲𝘀 Healthcare · Fintech · SaaS · E-commerce · Logistics · Telecom · IoT · Blockchain · Automotive · Media 𝗦𝗽𝗲𝗰𝗶𝗮𝗹𝗶𝘇𝗮𝘁𝗶𝗼𝗻𝘀 & 𝗥𝗼𝗹𝗲𝘀 ✔ Senior Java Developer · Java Spring Boot Developer · Java Backend Developer ✔ AWS Cloud Engineer · AWS DevOps Engineer ✔ Azure Cloud Engineer · Google Cloud Engineer ✔ AI Backend Developer · Full-Stack Developer (Spring Boot + React) ✔ AI Backend Developer · Full-Stack Developer (Spring Boot + React) Need a Java developer, backend developer, AWS developer, or AI developer who ships production systems — not prototypes? Drop me a message. 04/06/2026

I deliver production-ready Java backends that scale. With 100% Job Success and $10K+ earned across 22 contracts, I solve complex integration challenges, refactor legacy systems, and build APIs that handle real-world traffic. Client Testimonials: "Oleksandr is a genuine professional who was able to do a complex Java project for me." – Sweet Home 3D Client "Fast developer, always in contact, reasonable price policy. Would work with him again." – Spring Boot Projects Client What I Deliver: Spring Boot APIs – REST endpoints, authentication (Spring Security), database integration (JPA/Hibernate) Database Solutions – PostgreSQL schema design, query optimization, MongoDB aggregations Legacy Refactoring – Clean up messy code, introduce testing (JUnit/Mockito), containerize with Docker Third-Party Integrations – Payment gateways, calendar APIs, external data syncs Testing & Quality – Unit tests, integration tests, TestContainers for reliable deployments Tech Stack: Backend: Java (8/11/17/21), Spring Boot, Spring Data JPA, Spring Security, Hibernate Frontend: CSS/HTML, JavaScript/TypeScript Databases: PostgreSQL, MySQL, MongoDB APIs: REST, JSON/XML, Swagger/OpenAPI Testing: JUnit, Mockito, TestContainers DevOps: Docker, Maven, Git, GitHub Actions Principles: OOP, SOLID, TDD, GOF Design Patterns Why Hire Me: ✔ Fast turnaround – Average response time: 0-4 hours ✔ Clear communication – Tagged "Clear Communicator" by 5 clients ✔ Proven reliability – Top Rated, 100% Job Success, no failed contracts ✔ Real-world experience – From startups to clinical trial systems Have a backend challenge? Let's architect a solution together. 📩 Send me your project details, and I'll respond with a technical approach within hours.

I’m a Senior Java Engineer specializing in building and stabilizing backend systems with Spring Boot. I help companies design, develop, and maintain reliable backend services, with a focus on APIs, authentication, and production system stability. Most of my work is on existing systems where the goal is not just to write new features, but to fix issues, improve architecture, and ensure long-term maintainability. Over the last 10+ years, I’ve worked on enterprise-grade applications across telecom, infrastructure, and mapping domains. A significant part of my experience is in understanding complex legacy systems and making them stable, scalable, and easier to evolve. Key areas I work with: - Backend API development (REST, OpenAPI-driven design) - Authentication & authorization (OAuth2, OpenID Connect, JWT, Keycloak) - Spring Boot microservices and monolithic systems - Database design and integration (PostgreSQL, Oracle, MySQL) - Production debugging, root cause analysis, and stability improvements - AWS-based deployments and Dockerized applications Recently, I’ve also been working on AI-assisted backend integrations, using LLM APIs and tools like ChatGPT and Copilot to accelerate development, debugging, and system analysis. Core technologies: Java (8–21), Spring Boot, Spring Security, Hibernate/JPA, PostgreSQL, AWS, Docker, Maven/Gradle, Git. I work best in environments where systems are already live and need someone who can quickly understand the architecture, identify problems, and deliver reliable solutions.

Are you looking for a DevOps Engineer or System Administrator to help ensure your infrastructure is stable, scalable, and well-automated? You’re in the right place. My name is Sofiia, and I’m a DevOps Engineer / System Administrator with 6 years of hands-on experience working in a leading engineering company in Kyiv, Ukraine. I work as part of Skynix — a team focused on delivering reliable, scalable, and secure digital solutions. What I Do I help businesses build and maintain infrastructure that is stable, automated, and ready for growth. My experience includes: system administration and infrastructure support cloud infrastructure setup and maintenance CI/CD pipeline design and automation containerization and orchestration deployment and configuration management monitoring, reliability, and system optimization Core Technologies Kubernetes • Docker • Terraform • Ansible • Helm Jenkins • GitHub Actions • Spinnaker AWS • Azure Kafka • Consul • Istio • Calico • Kiali PostgreSQL • MySQL • SQLite • Firebase Java • JavaScript • Spring • Hibernate • jUnit • Postman Git • GitHub Business Domains Magento Commerce platforms WordPress marketing websites WooCommerce stores ERP / CRM systems corporate systems and access/security domains My Approach I focus on building infrastructure that is: reliable under production load automated to reduce manual errors scalable for business growth structured for long-term maintainability My goal is not just to “keep systems running,” but to ensure they are efficient, predictable, and safe for production environments. About Skynix Skynix is a full-cycle development company specializing in LAMP and JAM stack technologies, delivering complex web and infrastructure solutions using modern backend and frontend stacks. Why clients choose us: established in 2015 20+ engineers (senior, middle, junior levels) strong enterprise-level delivery experience reliable remote collaboration across time zones fast adaptation and strong engineering culture If you’re looking for a DevOps specialist who focuses on stability, automation, and system reliability — I’d be happy to collaborate.