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, Iโm 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 me๐ง:
๐ 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) โ Delivered scalable microservices and high-performance business logic for enterprise-grade applications.
- ORM & data access with Hibernate โ 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.
๐ Cloud-Native Platform Engineering
Specializes in building secure, scalable, cloud-native platforms using leading cloud providers:
- 8+ years of production experience with AWS โ Deployed scalable, secure, and high-availability applications.
- 9+ years of hands-on Azure expertise โ Delivered enterprise-grade solutions with Azure App Services, Azure DevOps, and SQL/Azure Storage.
- 5+ years of experience on Google Cloud Platform (GCP) โ Built and deployed containerized microservices using GKE, Cloud Run, and Firebase.
๐ 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.
๐ Full-Stack Leadership & Agile Team Management
- Led and mentored teams of 5โ25 developers through all stages of the SDLCโrequirements 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:
๐ค Partnered with 45+ SaaS companies to design and deliver secure, scalable platforms using Spring Boot, AWS, and modern cloud services.
๐ Helped 10 tech startups scale from MVP to productionโselecting the right tech stack, defining cloud-native architecture, and assembling strong dev teams.
๐ผ Enabled 5 client acquisitions through the development of enterprise-grade software that attracted major buyers and investors.
๐ญ Led a digital transformation project for a multi-billion-dollar oil company, delivering a secure, API-first platform that automated mission-critical operations.
๐งฉ 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:
๐ป Shoeby โ A fashion retail platform focused on modernizing the e-commerce experience with intuitive UI, product personalization, and seamless shopping journeys.
๐ป CellRebel โ Provides advanced mobile network analytics, helping telecom companies improve coverage and performance based on real user data.
๐ป Blade โ A technology-powered aviation company offering urban air mobility services, including helicopter and seaplane flights.
๐ป Matics โ A real-time operational intelligence system for manufacturers, offering production insights and process optimization across the factory.
๐ป MedischeScholing โ A medical e-learning platform that enables healthcare professionals to access, register for, and track accredited training and certifications.
โก๏ธ 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
Vadym K.
Full Stack .NET Developer | ASP.NET Core | SaaS Software Developer
Lviv, Ukraine
$35/hr$35 per hour5.0 (33) 56 jobs $1M+ total earnings
With 8+ years of experience in software development, I've delivered 35+ projects across various industries: fintech, healthtech, energy, industrial, maritime, defense, real estate, asset management, e-commerce, enterprise workplace platforms, and SaaS. I work as a Full Stack .NET Developer, building software, web applications, desktop and Windows applications, backend systems, RESTful APIs, and internal platforms that handle real production load, owning delivery from database design to deployment, release, and ongoing new features after launch.
๐ค I work with a reliable team, so we can fill any role on your project and become long-term partners. Don't hesitate to reach out, just tell me your required tech stack and budget :)
๐๐๐น๐น-๐ฆ๐๐ฎ๐ฐ๐ธ ๐๐ฒ๐๐ฒ๐น๐ผ๐ฝ๐บ๐ฒ๐ป๐
As a Full Stack .NET Developer, I've built React, Angular, and Next.js on frontend and .NET, Node.js on backend. One example is e-commerce fulfillment, where we integrated barcode scanning, inventory management, and multiple shipping-provider APIs, cutting order processing time by 35% and reducing packing errors close to zero. Another example is real-time monitoring frontends for industrial hardware, built for large-scale infrastructure projects where live data visualization replaced delayed manual checks.
๐ฆ๐ฎ๐ฎ๐ฆ ๐ฆ๐ผ๐ณ๐๐๐ฎ๐ฟ๐ฒ ๐๐ฒ๐๐ฒ๐น๐ผ๐ฝ๐ฒ๐ฟ & ๐๐ฒ๐ด๐ฎ๐ฐ๐ ๐ ๐ผ๐ฑ๐ฒ๐ฟ๐ป๐ถ๐๐ฎ๐๐ถ๐ผ๐ป
As a SaaS software developer, I build asset and fleet management systems in .NET Core and Angular. One example handled large concurrent asset volumes with automated reporting that saved operations teams over 10 hours per week. I'm also experienced building B2B SaaS suites that covers time-tracking, project management, and CRM, consolidating manual labor-cost tracking into a centralized system with approval workflows, AI-assisted insights, and analytics. I'm also open to legacy platforms and existing code with no documentation and daily production fires, rebuilding them into stable systems with proper code review, sprint planning, improved navigation, and design responsiveness across devices.
๐๐ฆ๐ฃ.๐ก๐๐ง ๐ช๐ฒ๐ฏ ๐๐ฃ๐ & ๐ช๐ฒ๐ฏ ๐๐ฒ๐๐ฒ๐น๐ผ๐ฝ๐บ๐ฒ๐ป๐
I build platforms on ASP.NET Core, ASP.NET Web API, EF Core, PostgreSQL, and Azure that automate complex business workflows end-to-end. One example is a lending and compliance system, where we integrated external CRM, pricing, and compliance services to replace manual data entry, cutting hours of manual processing per case. I'm also experienced modernizing legacy asset management systems and existing code for enterprise and defense clients using ASP.NET MVC, SQL, and Entity Framework, one such rebuild reduced manual reporting time by 70% while enabling real-time tracking and secure handling of sensitive operational data.
๐# & .๐ก๐๐ง ๐๐ป๐ด๐ถ๐ป๐ฒ๐ฒ๐ฟ
I optimize Microsoft SQL Server and PostgreSQL queries on reporting-heavy systems, one example reducing execution times by 60-80%. I'm also experienced designing microservices architectures on Microsoft Azure with automated CI/CD pipelines that cut release time by up to 50% for an enterprise client. Beyond .NET, I work with Python and Node.js for scripting layers, and Git and Docker for containerized, repeatable deployments.
๐ง๐ฒ๐ฐ๐ต ๐ฆ๐๐ฎ๐ฐ๐ธ:
โ Backend: .NET/C#, ASP.NET Core, ASP.NET MVC, ASP.NET Web API, .NET Framework, Python, Node.js
โ Frontend: Angular, React, Next.js, TypeScript, JavaScript, HTML, SCSS
โ Database: Microsoft SQL Server, PostgreSQL, SQL, Entity Framework Core
โ Cloud & DevOps: Microsoft Azure, Azure SQL, Azure Key Vault, Docker, Microservices, CI/CD, Git, Windows
โ Other: API Integration, RESTful APIs, Agile Development, AI integration
I take ownership of delivery end-to-end โ coordinating with stakeholders, and managing timelines and priorities so the project moves forward even when requirements shift.
๐ช๐ต๐ ๐๐น๐ถ๐ฒ๐ป๐๐ ๐๐ผ๐บ๐ฒ ๐๐ฎ๐ฐ๐ธ
I ask the right questions before writing the first line of code, flag problems early, and deliver reliable software development as a Full Stack .NET Developer and SaaS software developer. Whether it's a greenfield SaaS platform, a real estate or asset management system, an ASP.NET Core, Web API-driven enterprise system, or a legacy codebase that needs modernizing, I treat every engagement like it's going into production tomorrow.
๐ค Let's talk. I'm open to long-term collaborations as a Full Stack .NET Developer doing ASP.NET Core Web API development, SaaS software development, backend systems, enterprise platforms, microservices, web and desktop applications, plus API integration, database optimization, AI integration, and legacy system modernization. If you need a Full Stack .NET Developer or SaaS software developer who ships reliable platforms, let's talk.
Viktor I.
Extensive experience in Software Application Development
I am Agency Header, Project and Account Manager
Our Team have a huge Experience in Application Software Development and Intersystem integration:
โข AI - implementation
โข Back-End Development
โข Front-End Development
โข Oracle Application and DataBase Development
โข Web Development
โข Mobile App Development
We are working in Software Stack:
โข C#, ASP.NET and .NET Framework
โข Java
โข Angular
โข React and React Native
โข LLM, Machine Learning and Prompt Engineering
โข Next.js
โข Expo
We provide Outsourcing and Out-staffing service for our customers around the World
Personal Summary:
โข About 15 years of business application development
โข 5+ years Oracle Products Implementation and database development experience
โข Work in outsourcing and CIS projects
โข More then 7 years experience on managing positions: Header of software development center and company
โข Strong problem-solving and communication skills
โข Experience work with client request and sales support
โข Managing of development process
โข Team so-cooperation
โข Clear understanding of all stages in software development
โข Good background in requirements and support documentation
โข Good attention to details
โข Experience in ISO Certification
Main Background:
โข Operation manager
โข Resources and Budget planing
โข Oracle Application and Database Developer,
โข Project manager
โข Head of HR
Technical Skills:
โข Business application development: Oracle Application and Database
โข QA Automatisation
โข Infrastructure architecture development
I can build almost anything with Java and AI but my family assumes that includes fixig their Wi-Fi, printer, and TV๐
I'm a Java developer with 8+ years delivering production-grade systems from serverless AWS architectures to distributed microservices serving healthcare and fintech clients.
๐ช๐ต๐ฎ๐ ๐'๐๐ฒ ๐๐๐ถ๐น๐
โก As lead Java developer at my current company, managed a team of 8 engineers over 7 years โ delivering 4 production systems across healthcare, fintech, and AI verticals.
โก Designed serverless AWS infrastructure for a US longevity and healthcare platform as an AWS developer โ Lambda, AppSync, DynamoDB, Cognito, SNS/SQS, Stripe, HubSpot currently in production.
โก Led migration from monolithic Spring apps to distributed microservices โ reducing deployment complexity and enabling independent scaling per service.
โก 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.
โก Delivered an AI-powered workflow automation platform as an AI developer integrating Spring AI, Azure cloud, and automated Stripe subscription workflows.
โก 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 & ๐๐น๐ผ๐๐ฑ ๐๐ป๐ด๐ถ๐ป๐ฒ๐ฒ๐ฟ๐ถ๐ป๐ด
โ Currently operating as AWS developer on a live healthcare platform Lambda, AppSync, DynamoDB, Cognito, SQS/SNS/SES, S3, API Gateway, Route 53, CloudFormation
โ Experience as AWS developer across serverless, containerized (ECS/K8s), and IaC (Terraform, CloudFormation) environments
โ Also experienced across Azure (AKS, Azure DevOps) and GCP as multi-cloud backend developer
โ Kubernetes, Helm, Docker, OpenShift, Jenkins, Terraform the full DevOps chain every AWS developer deploys through
AI developer ๐๐ฎ๐ฝ๐ฎ๐ฏ๐ถ๐น๐ถ๐๐ถ๐ฒ๐
โ Delivered AI-powered backend services as AI developer using Spring AI automated content generation and workflow orchestration at scale
โ AWS AppSync + DynamoDB + Cognito pipeline for a live healthcare platform: the architecture an AI developer builds when latency and data integrity are non-negotiable
โ 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
โ As AI developer, built document intelligence features automated PDF tagging, structure remediation, and accessibility validation across large document corpora
๐๐ป๐ฑ๐๐๐๐ฟ๐ถ๐ฒ๐
Healthcare ยท Fintech ยท SaaS ยท E-commerce ยท Logistics ยท Telecom ยท IoT ยท Blockchain ยท Automotive ยท Media
๐ฆ๐ฝ๐ฒ๐ฐ๐ถ๐ฎ๐น๐ถ๐๐ฎ๐๐ถ๐ผ๐ป๐ & ๐ฅ๐ผ๐น๐ฒ๐
โ Senior Java Developer ยท Java Spring Boot Developer ยท Java Backend Developer
โ AWS Cloud Engineer ยท AWS DevOps Engineer
โ Azure Cloud Engineer ยท Google Cloud Engineer
โ AI Backend Developer ยท Full-Stack Developer (Spring Boot + React)
โ AI Backend Developer ยท 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
How it works
Post a job for freePost a job
Tell us what you need. Create your own job post or generate one with AI then filter talent matches.
Hire top talent fast
Consult, interview, and hire quickly, so you can meet the freelancers you're excited about.
Collaborate easily
Use Upwork to chat or video call, share files, and track project progress right from the app.
Payment simplified
Manage payments in one place with flexible billing options. Only pay for approved work, hourly or by milestone.
Don't just take our word for it
โUpwork provides an umbrella-level of security. I can see a talentโs work history and ratings. I can hold payments in escrow. I can communicate through Upwork Messages instead of working through my email address.โ
KD
Kim Darling
Verified
Emerald Tiger
โUpwork is the best platform to hire skilled professionals when we're not looking for a full-time employee. All the companies in our portfolio use Upwork to find talent across a wide range of fields.โ
DM
David Merry
Verified
Kinetic Investments
โOur very specific requirements can be a challengeโWith Upwork, weโre able to access a bigger community to ensure the success of our projects.โ
KK
Katja Krohn
Verified
Summa Linguae
How do I hire a Enterprise Software Developer in Ukraine on Upwork?
You can hire a Enterprise Software Developer in Ukraine on Upwork in four simple steps:
Create a job post tailored to your Enterprise Software Developer project scope. We'll walk you through the process step by step.
Browse top Enterprise Software Developer talent on Upwork and invite them to your project.
Once the proposals start flowing in, create a shortlist of top Enterprise Software Developer profiles and interview.
Hire the right Enterprise Software Developer for your project from Upwork, the world's largest work marketplace.
At Upwork, we believe talent staffing should be easy.
How much does it cost to hire a Enterprise Software Developer?
Rates charged by Enterprise Software Developers on Upwork can vary with a number of factors including experience, location, and market conditions. See hourly rates for in-demand skills on Upwork.
Why hire a Enterprise Software Developer in Ukraine on Upwork?
As the world's work marketplace, we connect highly-skilled freelance Enterprise Software Developers and businesses and help them build trusted, long-term relationships so they can achieve more together. Let us help you build the dream Enterprise Software Developer team you need to succeed.
Can I hire a Enterprise Software Developer in Ukraine within 24 hours on Upwork?
Depending on availability and the quality of your job post, it's entirely possible to sign up for Upwork and receive Enterprise Software Developer proposals within 24 hours of posting a job description.
Find more freelancers
Top cities for Enterprise Software Developers in Ukraine