Hire the Best J2EE Developers
in Ukraine
Kyiv, Ukraine
I can code in a wide range of languages and frameworks. Here's a quick overview of what I can help with: Languages: Python, JavaScript, TypeScript, Java, C#, PHP, Swift, Kotlin, and more. Frontend: React, Vue, Angular,Next.js, HTML/CSS, and more. Backend: Node.js, Spring Boot, .NET, and more. Other areas: Databases (SQL, NoSQL, ORMs) DevOps (Docker, CI/CD, Infrastructure as Code) APIs (REST, GraphQL, gRPC) Testing (unit, integration, e2e) Algorithms and data structures System design and architecture I can write new code from scratch, debug existing code, refactor, optimize, explain concepts, or help you work through a design problem. Just let me know what you'd like to build or fix, and I'll jump right in!
- J2EE
- Customer Relationship Management
- ZK Framework
- Database Modeling
- Enterprise Resource Planning
- Software Architecture & Design
Kryvyy Rih, Ukraine
Full-stack developer specialising in Flutter for sleek, cross-platform frontends and Java/GCP/AWS for robust backend systems. AI adopter. Flutter Development. 5 years of experience creating high-performance cross-platform applications with Flutter, covering mobile, web, and desktop platforms. Proven ability to develop complex solutions, including networking, video streaming, marketplaces, and social applications. Java Enterprise Development. 13 years of hands-on experience building robust Java enterprise applications, specializing in custom development for open-source ERP systems. Strong expertise in business process automation and enterprise data modelling. Backend Expertise. Capable of designing and integrating backend solutions, whether leveraging cloud services like Firebase and AWS or implementing custom Java-based architectures. Experienced in implementing and automating testing processes, including unit testing and integration testing, to ensure software reliability and maintainability. With a deep understanding of software development and a passion for creating scalable, efficient applications, I bring a results-driven approach to every project.
- J2EE
- Push Notifications
- Java
- Kotlin
- Android App Development
- Dart
- Firebase
- Flutter
- Spring Framework
- Apache OFBiz
Vinnitsa, Ukraine
⭐⭐⭐⭐⭐ 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
- SQL
- Git
- JavaScript
- Node.js
- Python
- MongoDB
- Angular
- MySQL
- Software Development
- Software Architecture & Design
- Java
- Docker
- Amazon Web Services
- Spring Boot
- DevOps
- React
- Artificial Intelligence
- Machine Learning
- Natural Language Processing
- Desktop Application
Lviv, Ukraine
🧠🤖I design, build and scale AI Agent solutions that automate real business workflows - not demos, not experiments, but production-ready systems that actually run companies. If you’re looking to build AI Agent that can think, act, integrate with your tools and improve over time, you’re in the right place. I work as an AI Agent Developer and Agentic AI Developer, helping founders, teams and companies turn complex processes into reliable AI Agent Automation systems - from internal ops to customer-facing products. 📊 Numbers that reflect real AI Agent outcomes ✅ 12+ years in AI systems, AI Agent development, full stack & software engineering ✅ 85+ digital products delivered, including AI Agent platforms and AI automation systems ✅ 57+ MVPs launched - many built around an AI Agent or agentic workflows ✅ 40+ production systems with AI Agent automation used by real users ✅ 32+ products prepared for investor demos, AI feasibility reviews & technical due diligence ✅ $2.2B+ raised by products I helped build or scale ✅ 30-45% faster launches using reusable AI Agent frameworks and automation pipelines ✅ 40% fewer post-launch issues thanks to stable AI Agent logic and controlled integrations ✅ 100% code ownership - every AI Agent stays fully in your repositories ✅ Clients working with me for 7+ years 🤝 Most projects start with one clear goal: replace manual work with an AI Agent that can operate independently. That can mean: → An AI Agent that handles support, research or acts as a sales agent embedded into real business workflows → A backend AI Agent orchestrating APIs and business logic → An AI Voice Agent for calls, bookings or assistants → A multi-agent system acting as a full AI Automation Agency replacement As an AI Agent Builder, I create systems that reason, plan and execute - not just respond. This includes: → AI Agent Creation using modern agentic patterns → AI Agent Automation across CRMs, databases, internal tools and business development workflows → AI Agent n8n workflows for orchestration and scalability → Custom AI API Integration with existing platforms Each AI Agent is designed to be reliable, explainable and easy to extend. 🧩I approach every project as an AI Developer first, not a prompt engineer. As an Open AI Developer and AI Developer LangChain practitioner, I build AI Agent systems with: • Proper state management • Tool calling and function execution • Memory, context control and fallback logic • RAG pipelines (as an AI Developers RAG specialist) • AI-first architecture This allows each AI Agent to retrieve knowledge, reason over it and act safely in real environments. When needed, I design AI Agent Automation stacks that behave like a full AI Agency, but fully owned by you. 💡Beyond one-off bots - real agentic systems A simple chatbot isn’t an AI Agent. A real AI Agent understands goals, chooses actions and completes tasks end-to-end. That’s where Agentic AI Developer experience matters. I build: → Single-purpose AI Agent tools (e.g. Pinterest marketing AI Agent or Etsy marketing AI Agent) → Multi-agent systems coordinating tasks → Internal AI Agent Creator platforms → Long-running AI Agent services Whether you need an AI Agent Builder for MVP speed or a production-grade AI Agent Automation system, the focus stays the same: stability, control and measurable impact. Strong foundations first - AI when it makes sense 🧠🔧 Every AI Agent I build sits on solid engineering foundations. I combine AI Agent Development with backend systems, APIs and infrastructure so your AI Agent doesn’t collapse under real usage. ⚙️This includes: • Backend services for AI Agent logic • Secure AI API Integration • Scalable pipelines for AI Agent Automation • Monitoring, logging and iteration loops AI should reduce chaos. 🧭 Not every problem needs AI from day one If your project doesn’t require advanced AI immediately, I also help design and build data pipelines, backend services, APIs, dashboards and MVP infrastructure that work perfectly on their own. This keeps products stable, cost-efficient and flexible - ready to introduce ML or AI features later, without forcing complexity too early. 🔍 How I usually work on AI Agent projects 1️⃣ Understand business goals, constraints and where an AI Agent creates real leverage 2️⃣ Design the right AI Agent architecture (tools, memory, APIs, automation) - not hype 3️⃣ Build and refine the AI Agent iteratively with clear milestones and validation 4️⃣ Test, launch, monitor and evolve the AI Agent in real-world usage 🧰 Core tech stack - Frontend: React, Next.js, TypeScript - Backend: Node.js, Python (FastAPI, Flask, Django) - AI & Agents: OpenAI APIs, LangChain, RAG pipelines, Agentic AI patterns - Automation: AI Agent n8n, custom orchestrators - APIs: REST API, GraphQL, Webhooks - Databases: PostgreSQL, MongoDB, Redis - Cloud & DevOps: AWS, Docker, CI/CD - Architecture: SaaS platforms, AI Agent Automation, clean code Have an AI idea in mind? Let’s make it live.
- Python
- JavaScript
- TensorFlow
- Machine Learning
- Deep Learning
- Artificial Intelligence
- AI Bot
- Natural Language Processing
- Computer Vision
- Data Science
- Data Analysis
- PyTorch
- Neural Network
- Lead Generation
- Data Entry
- Automation
- API Integration
- Data Scraping
- Zapier
- AI Agent Development
Ukrainka, Ukraine
👋 Hello! Senior Java Developer, Team Lead & Architect with 10+ years of hands-on experience with 10+ years of hands-on experience building scalable, high-load web and mobile applications. I mainly work with Java backend, JavaScript, TypeScript, Oracle, Postgres databases. My core backend work is centered on Spring Boot, focusing on API development and production-grade RESTful services backed by PostgreSQL. My focus is on backend software architecture, ensuring scalability, clean boundaries, and long-term maintainability. ✔️ Ready-to-Use Integrations I can accelerate your product using proven, production-ready integrations: 🚀 AI & LLMs: ChatGPT, LLaMA, Mistral (text, images, vision, automation) 🚀 Payments: Stripe (card payments & transfers) 🚀 Voice & Media: ElevenLabs (speech & voice AI) 🚀 Communication: Zoom (voice & video integrations) My Specialization: ✅ Backend & Architecture: Java (10+ years): modern Java (Lambdas, Streams, Date/Time API), Spring (9+ years): Spring Boot, Spring Data, Spring Cloud for microservices and distributed systems, and Java EE: REST APIs, SOAP, JPA, third-party integrations ✅ Security & Frameworks: Keycloak with OAuth2 and JWT-based authentication, JHipster, Swagger, Liquibase, Axon, Vaadin, ORM: Hibernate, Blaze-Persistence ✅ Databases & Messaging: SQL (10+ years): PostgreSQL, MySQL, MariaDB, Oracle, NoSQL: MongoDB, Redis, Hazelcast, Messaging: Kafka, ActiveMQ, RabbitMQ, Zookeeper, Firebase Messaging ✅ DevOps & Observability: CI/CD: Jenkins, Docker, Kubernetes, ELK Stack (Logstash, Elasticsearch, Kibana) ✅ Quality & Delivery: Testing: JUnit, Mockito, Spring Test, Unit & Integration testing, Full SDLC, code reviews, refactoring, clean architecture 💡 Let’s discuss how I can help you build a reliable, scalable solution!
- Java
- Spring Boot
- RESTful API
- Apache Kafka
- PostgreSQL
- Spring Framework
- Spring Cloud
- Docker
- Kubernetes
- OAuth
- Hibernate
- CI/CD
- API Development
- Software Architecture
Kyiv, Ukraine
🏆 10+ years of experience as Software Engineer 🎯Delivered for insurance, telecommunications, security/surveillance domains, business management platforms ✅ Frameworks & Tools: Java/J2EE, Spring Boot, MSSQL, MongoDB, Docker, Hibernate, REST, Liferay, JUnit, Jenkins, Maven, Ant, API Integration. Java Backend development is one of my strengths, I will bring to you apps with modern, attractive, simple, and easy to use functionality. I'm very friendly, straightforward, honest, hard working and very easy to work with. I am looking for long-term relationship with clients, come and work with me to find out that I am your excellent partner. I'm looking forward to know more about your app idea to bring it to life!
- Java
- Swing
- Hibernate
- SQL
- MongoDB
- Git
- JBoss EAP
- Apache Tomcat
- REST API
- Docker
- Jenkins
- Insurance Software
- JUnit
- Spring Boot
- XML
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