Hire the Best Core Java Developers
in Ukraine

👋 Need a high-load Java platform that scales without a glitch? 🚀 I provide full-stack ownership with Spring Boot and React Native, turning complex ideas into secure, production-ready reality. Backed by 20+ years and 100+ delivered projects, I build code that works for your bottom line, not just your repo. Check out my page to see my portfolio! 🛡️ As a Java Developer I've built high-load backend systems, REST AP payment solutions document processing platforms, and business applications used by thousands of users. As a Full Stack Developer and React Native Developer I've helped startups and growing companies launch scalable products while maintaining security, performance, and compliance. Throughout my career, I've worked with startups, established businesses, and enterprise clients, helping them transform ideas into reliable software products. My experience covers the entire development lifecycle, from architecture planning and technical discovery to development, deployment, optimization, and long-term support. My expertise includes Java Developer Spring Boot React Native AWS PostgreSQL Docker Kubernetes microservices cloud infrastructure and secure software architecture 💪 Full Stack Java Developer Expertise ✔️ 20+ years of Java development 100 successful projects using Java, Spring Boot, Spring Security, Hibernate, and enterprise architectures ✔️ Full Stack Development covering backend architecture database design frontend implementation and React Native mobile applications ✔️ Spring Boot Development, REST API microservices cloud-native applications and high-performance backend systems ✔️ Backend Architecture, distributed systems, 50 third-party integrations, authentication systems, and secure API development ✔️ PostgreSQL MySQL Redis AWS Docker Kubernetes CI/CD performance optimization and legacy system modernization ✔️ Extensive experience designing business-critical applications where scalability, maintainability, security, and long-term growth are key requirements ✔️ Experience integrating payment gateways, healthcare systems, cloud services, identity providers, and external enterprise platforms ✔️ Strong understanding of software architecture, design patterns, clean code principles, and modern development practices ✔️ Experience leading technical initiatives, collaborating with distributed teams, participating in code reviews, and helping businesses make technology decisions 🏥 Healthcare Software Development Expertise As a Senior Java Developer and Full Stack Developer, I've built secure and HIPAA-compliant healthcare software for startups, clinics, and digital health companies. ✔️ 100+ healthcare applications including EHR/EMR systems, telemedicine platforms, patient portals, and engagement solutions ✔️ 80+ FHIR & HL7 integrations for healthcare interoperability and secure data exchange ✔️ 150 React Native healthcare apps with Apple HealthKit, Google Fit, BLE, and real-time health monitoring ✔️ 100+ healthcare features delivered, improving patient engagement and clinical workflows ✔️ 50+ HIPAA-compliant architectures with encrypted storage, audit logging, RBAC, and secure APIs ✔️ 100 Java Spring Boot backend systems with up to 99.9% uptime ✔️150+ healthcare workflow automations, provider portals, appointment management, and patient communication platforms 💳 Fintech Software Development Expertise As a Full Stack Java Developer I've built PCI DSS-compliant fintech platforms focused on payments, identity verification, and transaction security. ✔️ 50+ Stripe, Apple Pay, Google Pay, and 3D Secure (3DS) integrations ✔️ 20+ KYC & AML workflows for onboarding and compliance automation ✔️ 100+ payment features delivered, reducing friction and improving transaction success ✔️ 25+ payment platforms, transaction systems, and financial API integrations ✔️ 15+ PCI DSS architectures with encryption, tokenization, audit logging, and secure authentication ✔️ 50+ financial reporting, payment workflows, transaction monitoring, and compliance solution 🏆 Key Results | Java Developer Spring Boot | Full Stack Java Developer | React Native ✔️ 20+ years of commercial experience as a Full Stack Java Developer ✔️ 100+ enterprise projects across Healthcare, FinTech, SaaS, and AI ✔️ 55+ AI-powered products using OpenAI, Claude API, FastAPI, AI Agents & RAG ( use Lovable \ Bollt.new \ Base44 and etc ) ✔️ Up to 100% uptime for mission-critical healthcare and fintech systems ✔️ Up to 40% higher patient engagement through digital health solutions ✔️ Up to 25% lower payment decline rates with optimized payment workflows ✔️ Up to 35% faster application performance and scalability improvements ✔️ Up to 90% fewer security vulnerabilities with secure architectures 📩 Looking for a technical partner who understands both technology and business goals? I help companies build, scale, and modernize Healthcare Fintech SaaS and Enterprise products using Java Spring Boot Full Stack technologies and React Native

Hello, my name is Dimytro. I am Java developer from Kyiv, Ukraine. I am developing Java since 2019.

I am a Senior Fullstack Developer with over 15 years of hands-on experience in building and scaling Java , C# / Net , Angular applications for startups, enterprises, and SaaS platforms. Currently, I’m working as the Chief Technology Officer at InventorSoft, a software development agency specializing in web and mobile solutions. I bring a strategic mix of technical depth, team leadership, and product vision to every project. Why hire me🧐: 📌 Expert in Scalable Java and .Net Architectures - Over 15 years of experience in developing Java, .Net, C#, Angular scalable applications from different domains. - Backend systems built with Spring Boot (15+ years) – Delivered scalable microservices and high-performance business logic for enterprise-grade applications. - ORM & data access with Hibernate – Applied advanced ORM techniques for efficient database interactions, query optimization, and data integrity in distributed systems. - Frontend development with Angular & Thymeleaf Designed and delivered 200+ robust backend systems for SaaS products, e-commerce platforms, and enterprise clients. 📌 Cloud-Native Platform Engineering Specializes in building secure, scalable, cloud-native platforms using leading cloud providers: - 8+ years of production experience with AWS – Deployed scalable, secure, and high-availability applications. - 9+ years of hands-on Azure expertise – Delivered enterprise-grade solutions with Azure App Services, Azure DevOps, and SQL/Azure Storage. - 5+ years of experience on Google Cloud Platform (GCP) – Built and deployed containerized microservices using GKE, Cloud Run, and Firebase. 📌 API-First & Cloud-Native System Design - Strong background in API integration and microservice architecture. - Created high-performance APIs for platforms serving 50K+ users, ensuring seamless third-party integration and scalability. - Experienced in Docker & Kubernetes, enabling CI/CD pipelines and resilient containerized systems. 📌 Full-Stack Leadership & Agile Team Management - Led and mentored teams of 5–25 developers through all stages of the SDLC—requirements gathering to deployment and maintenance. - Specialized in building cross-functional teams for backend-heavy systems, modern UIs (React, Angular, Thymeleaf), and DevOps automation. My latest achievement as a Software Architect: 🤝 Partnered with 45+ SaaS companies to design and deliver secure, scalable platforms using Spring Boot, AWS, and modern cloud services. 🚀 Helped 10 tech startups scale from MVP to production—selecting the right tech stack, defining cloud-native architecture, and assembling strong dev teams. 💼 Enabled 5 client acquisitions through the development of enterprise-grade software that attracted major buyers and investors. 🏭 Led a digital transformation project for a multi-billion-dollar oil company, delivering a secure, API-first platform that automated mission-critical operations. 🧩 Technologies I Specialize In - Languages/Frameworks: Java, C#, .Net, Spring Boot, Hibernate, Thymeleaf, .Net Core - Cloud Platforms: AWS (8+ years), Azure (9+ years), Google Cloud (5+ years) - DevOps Tools: Docker (7+ years), Kubernetes (5+ years) - Integration & Architecture: RESTful API integration, microservices, clean architecture, CI/CD pipelines Clients that I am proud of: 💻 Shoeby – A fashion retail platform focused on modernizing the e-commerce experience with intuitive UI, product personalization, and seamless shopping journeys. 💻 CellRebel – Provides advanced mobile network analytics, helping telecom companies improve coverage and performance based on real user data. 💻 Blade – A technology-powered aviation company offering urban air mobility services, including helicopter and seaplane flights. 💻 Matics – A real-time operational intelligence system for manufacturers, offering production insights and process optimization across the factory. 💻 MedischeScholing – A medical e-learning platform that enables healthcare professionals to access, register for, and track accredited training and certifications. ➡️ Learn more about other projects on the InventorSoft portfolio Keywords: Java, Backend, Developer, Fullstack, Web, Cross-Platform, Mobile, Application, AI, OpenAI, Service, App, Development, Engineer, Integration, Build, Website, Expert, Spring boot, MySQL, Development Team, Integrated, SaaS Platform, remote, Full-stack, Senior, Software, Client Management, GraphQL, API, .NET, Asp.net, Programmer, Technical Lead, Dashboard, MVC, Developers, ASP.NET, AspNetZero, core, software, MAUI, C#, Angular, .Net, Core, Principal, Performance, Scalability, Microsoft, Blazor, SQL, Server, Frontend, React, Ruby on Rails, RoR/React, front-end, Tailwind, feature, TailwindCSS, Technical Staff, JavaScript, ROR

⭐⭐⭐⭐⭐"Mykyta has exceptional characteristics both in hard and soft skills. He took a part in complex software development projects as a part of a large mixed group. The feedback from our customers and team is always positive." ⭐I'm the highest-rated and highest-earning Java & Groovy freelancer on Upwork with numerous 5-star reviews, including overly positive feedback. ⭐ I've developed different custom specific software using modern java & groovy software using microservice and monolithic architecture, improved performance, refactored and tested in next business domains: ✅ Utilities ✅ Fintech ✅ Auto ✅ Security ✅ Cryptocurrency ✅✅✅ Brief information about me! ✅✅✅ ✅ Senior Java & Groovy Software Engineer ✅ Specializing in back-end development | Cloud Integrations (AWS, GCP, Azure) ✅ I have over 6.5+ years of experience in Java development ✅ Experienced both in developing software from scratch and maintaining large existing projects ✅ I have hands-on experience in developing back-end web services with micro-service or monolith architecture using Java technology stack, including modern cloud-based solutions. 🌟 WHY YOU SHOULD CHOOSE ME OVER OTHERS? 🌟 ✅ Clients' feedback: I am concentrating on giving VALUE and bringing SUCCESS to all of my customers, earning their TRUST and helping them to EARN MONEY. ALL customers' feedback on my Profile is extremely important to me and proves the value that I provide. ✅ Responsiveness: Communication is extremely important as a part of every business ever existed, and once it is fast and clear, it may lead to awesome results, that's why I tend to be available for my customers in no time, reply fast and clear, as well as I try to be fair, understanding and responsive. ✅ Kindness and Empathy: My main personal principles that I implement in every facet of my life. Treating everyone with respect, aiming to understand the whole situation or problem to solve the pain of my client, and constantly work to IMPROVE the client's product. 🙋🏼‍♂️I am eager to work with you, to provide high-quality code, reliable, consistent solutions, solve your problems and bring success to your business. Contact me, and we will discuss how we can work together to FULLY meet your Business Needs, follow your business rules, and bring you success. A big area of expertise: - REST API design and development - Horizontally scalable and highly available systems - Automating development workflows and deployment pipelines - Micro-service design and development - Design and development of decentralized applications (DApps) - Monitoring, log aggregation - Java and Groovy development - Service-Oriented architecture - Spring Framework (including cloud-based stack) - Experience in NoSQL Development (MongoDB, Neo4j) - Performance and Scalability Optimization Huge Skills & Technologies set: - Java/Groovy - AWS - Linux (with distributives) - Jenkins, CircleCI, Rundeck, Rancher - Docker - MySQL, Postgres - Redis, MongoDB, Neo4j. - RabbitMQ, ActiveMQ, SQS, RabbitMQ

I can build almost anything with Java and AI but my family assumes that includes fixig their Wi-Fi, printer, and TV😅 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? Drop me a message 24/08/2026

I am a Java developer with over 14 years of experience building full stack applications, enterprise systems, and SaaS platforms 🚀 My focus 🎯 is on using Java, Spring Boot, React.js, PostgreSQL, and AWS to deliver reliable, scalable software. As a Java developer, I have delivered dozens of projects across industries and use cases. My backend work is built entirely with Java. I create secure APIs and microservices using Spring Boot. I have deep experience in system architecture, backend performance, and database design. Every project I take as a Java developer is written with clean, maintainable Java code. I know how to structure services that scale. As a Java backend developer, I have built and maintained systems for high-load traffic, third-party integrations, and complex business logic. I manage full backend pipelines, from architecture and development to deployment and monitoring. I use Spring Boot and follow best practices every Java developer should apply. I also work as a full stack Java developer, connecting Java backends with React.js and JavaScript frontends. I create dashboards, user interfaces, and admin tools that are fast, stable, and fully integrated. I know how to deliver full stack features without bottlenecks. I have led teams as a senior Java developer, mentoring other developers, reviewing Java code, and improving team performance. My clients rely on me not just for development, but also for decisions about architecture, data structure, and deployment strategy. As a Java developer, I care about the full picture. In most projects, I take the role of a Java spring developer and own the backend infrastructure. I work with Docker, PostgreSQL, REST APIs, and cloud services. I often work independently, taking full responsibility for both backend and frontend parts as a full stack developer. Being a professional Java developer means I deliver production-ready code, meet deadlines, and communicate clearly. I work well with teams or as a solo contributor. My background as a Java backend developer and Java spring developer allows me to adapt to different project needs. If you need a Java developer who can work on backend systems, full stack features, or cloud-based platforms, I am ready to help. Whether you need a senior Java developer, a Java backend developer, or a reliable full stack Java developer, I can take your project from idea to production. 🛠️ Core Skills: - Java developer - Java backend developer - Full stack Java developer - Java spring developer - Spring Boot microservices - React.js and JavaScript - PostgreSQL, AWS, Docker Let’s talk if you need a results-driven Java developer to join your team or take over delivery. ‼️ Message me for a free 40-minute consultation ‼️