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in Poland

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Rating is 4.7 out of 5.
4.7/5
Based on 181 client reviews
Vladyslav P.

Wroclaw, Poland

$35/hr
4.9
11 jobs

I'm a Full Stack Developer and .NET Developer with 10+ years building web applications that businesses actually run on. I take an idea and ship it — front end, back end, database, deployment — and I've done it for products still serving customers a decade later. ✦ WHAT I DO BEST My core stack is .NET and C#. As a .NET Developer I build secure, scalable back ends with .NET Core and ASP.NET Core, expose them as clean ASP.NET Web APIs (REST), and back them with Entity Framework and SQL Server, PostgreSQL. As a Full Stack Developer I pair those APIs with responsive front ends in Angular, React, or Blazor, then deploy and scale on Azure with Azure DevOps, Docker, and CI/CD. When a product needs AI, I wire proven models — often through a thin Python layer — into the application without breaking what already works. And when a templated WordPress or Shopify build has hit its ceiling, teams bring me in to rebuild it as a custom .NET web application that can actually grow. ✦ PROOF OF WORK Longevity is the point. I once took a rough idea from an automotive client and built it into an e-commerce platform that has served customers for nearly 15 years and still runs today. As the lead .NET Developer on Launch Control, a real-estate SaaS, I refactored the core and made the system 50x faster. I also built SiftScore, an AI-powered talent-acquisition platform that uses the OpenAI API to source and score large datasets. Across fintech, real-estate, and healthcare I've owned the full lifecycle as a Full Stack Developer: requirements, architecture, build, go-live. 🚀 SaaS MVP (From Idea → Production) When a client starts from a rough idea, I take it the full way: requirements, architecture, prototyping, build, and go-live on Azure. As a Full Stack Developer I've shipped .NET SaaS MVPs for fintech, real-estate, and conveyancing platforms — clean, maintainable code with the scalability and monitoring to grow once real customers arrive. ✦ AI Integration for Existing Products I add AI features when a product actually needs them. The fastest, most cost-efficient path is usually integrating a proven model — OpenAI, Claude, or Gemini, often through a thin Python layer — rather than training your own. I add chatbots, automation, and smart search to existing web apps. Most AI features fail not because of the model but because the surrounding .NET architecture wasn't built to support it — and that's where a senior Full Stack Developer earns their keep. ⚙️ Modernizing Existing .NET Systems - without the rewrite If you have a .NET or C# application that needs work, I optimize performance, refactor legacy code, upgrade aging ASP.NET back ends, and migrate data access to Entity Framework Core — refactored against SOLID principles, without freezing feature work. Stuck on an old ASP.NET WebForms app? You don't have to gamble on a big-bang rewrite. As a .NET Developer I migrated a WebForms spare-parts store — 20M+ products across 100+ suppliers — to ASP.NET MVC by running both side by side in one solution, so the business kept selling while the modernization happened underneath it. The same incremental approach moves teams off PHP, Laravel, or legacy WordPress builds and onto a maintainable .NET stack: ship value continuously, retire old code gradually, never go dark. ✦ Legacy .NET project modernization Old code isn't the enemy — downtime is. As a .NET Developer, I modernize legacy ASP.NET and ASP.NET MVC systems by introducing a clean API layer, migrating data access to Entity Framework Core, and refactoring against SOLID principles, all without freezing feature work. As a Full Stack Developer, I migrate the application page by page behind a feature flag, so new and old run together in production and you can switch any screen over — or roll it back instantly — without disrupting users. Whether it's an ASP.NET MVC application that has grown brittle or a WebForms system that needs a path forward, I find the route that lowers risk: incremental, tested, and reversible at every step. ✦ ENTERPRISE-GRADE .NET ARCHITECTURE My work as a Full Stack Developer goes deeper than features. On a large enterprise fintech platform built on microservices, as a Full Stack Developer I designed how the team builds — onboarding developers, setting architectural standards, and structuring a clean, maintainable .NET codebase that scales. As a .NET Developer with a decade across .NET Framework, .NET Core, ASP.NET, and ASP.NET MVC, plus an M.Sc. in Applied Mathematics behind the design decisions, means I build systems meant to last years, not quarters. I focus on web rather than native mobile apps in Flutter or React Native; on the .NET side I also ship cross-platform with .NET MAUI. I'm a web developer — my C# and .NET expertise powers web applications. ✦ HOW WE'LL WORK If you need a Full Stack Developer or .NET Developer who can take something from rough idea to production — and keep it running for years — let's talk about the fastest path to shipping it.

  • Web Application
  • C#
  • React
  • Node.js
  • .NET Core
  • API Integration
  • Full-Stack Development
  • .NET Framework
  • ASP.NET MVC
  • ASP.NET
  • ASP.NET Core
  • Angular
  • WordPress
  • Microsoft SQL Server
  • Microsoft Azure
  • JavaScript
  • PHP
  • Python
  • Software Development
  • ASP.NET Web API
Ilya P.

Warsaw, Poland

$35/hr
5.0
20 jobs

Full Stack Developer & AI Developer / SaaS Architect — I'm a Web Application Developer & AI Engineer focused on AI Solutions & SaaS Development. Strong skills as an AI SaaS Developer, Senior Python Developer, and React Developer. Top Rated Plus | 100% Job Success | Only 5-star reviews ⭐⭐⭐⭐⭐ You'll get your AI SaaS prototype in 2 days, your AI-Powered SaaS MVP or AI solution shipped in 6-12 weeks🚀 🎓 BACKGROUND I've Master’s in Data Science & AI, currently preparing a PhD in AI. I’m a Senior Full-Stack Developer / AI Developer & AI Solution Architect with more than 8 years across 60+ projects. 💬 "Ilya led the work as the AI SaaS solutions architect & AI full-stack engineer, taking ownership of the overall architecture and delivery. Ilya delivered as an AI SaaS developer — balancing product, engineering, AI work without losing speed or quality. Ilya was exactly the kind of fractional CTO & engineering partner I was looking for. Highly recommend Ilya" — Jake Kinzelberg, Founder, Insurance AI SaaS, USA 💬 "Thanks to Ilya for developing my AI-powered SaaS. Ilya proved himself as an excellent AI Software developer & fullstack developer, proposed a clean UI UX SaaS Web design, built a solid backend with Python FastAPI, a front end with React" — Dmitri Dalla-Riva, Founder of Aidtrade, Australia 🎯 WHAT I DO I ship production-grade AI SaaS / AI product end-to-end. You come to me when you need: 🔹 SaaS MVP in weeks — built on architecture that scales beyond the prototype 🔹 AI development, AI Integration, LLM integration — RAG pipelines, AI agent SaaS, Voice Agent 🔹 Full Stack development delivery — one senior point of contact, one accountable owner 🔹 A technical co-founder mindset — scoping the SaaS development, making architecture decisions, owning the result 🛠 HOW I WORK As a Senior Full Stack Developer (React Python), AI Architect, I lead a small team — Senior Backend Engineer (Python Node.js), Frontend (React Angular Next.js), Full Stack Developer AI (JavaScript Vue.js jQuery Bootstrap), AI/ML Engineer, Mobile App Developer (Flutter), UI UX designer / SaaS UX designer — all under my direct coordination. In my work as a Full Stack AI SaaS developer & Python developer, I act as your delivery manager: one point of contact, the delivery capacity of a small agency. I work with Founders as a long-term Partner — calm execution, clear communication 📌 AI-Powered SaaS Development As a Full Stack Web Developer / AI SaaS full stack developer / SaaS AI Software Architect, I design SaaS Startup MVP that scale beyond the first version — multi-tenant architecture, role-based access, billing, webhooks, pipelines 🔹 SaaS architecture → Multi-tenant SaaS, RBAC, OAuth2, Stripe, AI API Integration 🔹 SaaS data layer → PostgreSQL, Redis, Supabase, multi-tenant isolation 🔹 SaaS infrastructure → Docker, AWS, Azure, Vercel, Cloudflare, CI/CD 🔹 SaaS delivery & AI MVP Development → SaaS design, MVP-to-production in 6 weeks 📌 AI Software Development As an Anthropic / OpenAI Developer, Data Scientist & Machine Learning Engineer, I integrate LLM & RAG into SaaS & Websites 🔹 AI/LLM integrations → Claude, ChatGPT-5, LLaMA, Mistral — fine-tuning, prompt design 🔹 RAG & Vector DB → LangChain, FAISS, Qdrant, Pinecone, ChromaDB, pgvector — Voyage embeddings, hybrid search inside SaaS, AI SEO 🔹 Generative AI → Stable Diffusion, SDXL, LoRA — custom image pipelines 🔹 AI ML Engineer → AI automation, deep voice agent, Computer Vision, MCP integrations, dashboards, LLM-powered SaaS 📌 Full Stack Development / Web Application Development As an AI Machine learning / Python Full Stack Developer & React developer / Senior Web Developer Python, I own the SaaS product end-to-end — ReactJS Next.js frontends, Python FastAPI Node.js backends with Superbase; MERN stack, PHP, Webflow / WordPress developer. 🔹 Front end developer → React, Next.js, TypeScript, Tailwind CSS, JavaScript 🔹 Backend developer → Python FastAPI, Django, Node.js, REST API development, GraphQL APIs 🔹 Real-time → WebSockets, Server-Sent Events for streaming AI 🔹 Web Application architecture & Web Development → modular monorepos, microservices 🤖 SENIOR AI-AUGMENTED DEVELOPMENT As a Senior AI Engineer / Python Backend Developer, I use modern AI tools for faster AI development: GitHub Copilot for coding, ChatGPT for reasoning, Cursor for refactoring, Claude Code with MCP for architecture, Replit for prototype testing, Lovable for MVPs prototyping, Bolt.new for web app experiments, v0 by Vercel for UI generation 🏆 MY UPWORK TRACK RECORD ✅ Top Rated Plus Expert ✅ 100% Job Success Score ✅ $200K+ earned delivering SaaS & AI Solutions ✅ 16 completed Upwork jobs ✅ 5-star average rating ✅ Upwork Skill Certified — Python Developer; Back-End Development 🤝 LET'S WORK TOGETHER If you're building SaaS or AI solution — you need a technical partner who ships, owns, thinks like a co-founder — message me. You’re taken from idea to deployment — faster and smarter

  • Web Application
  • CSS
  • HTML
  • SaaS
  • SaaS Development
  • Full-Stack Development
  • Back-End Development
  • Artificial Intelligence
  • Machine Learning
  • Python
  • React
  • JavaScript
  • Node.js
  • PHP
  • WordPress
  • Software Development
  • SQL
  • Git
  • Web Development
  • Natural Language Processing
Vitalii D.

Warsaw, Poland

$38/hr
4.8
30 jobs

🌟 Fullstack Developer with 15+ years of experience | TOP 50 Tech Visionaries in the US by InterCon | ex-mentor for Facebook Development Circle | CTO experience | Delivering High-Quality Solutions for Web, Cloud, and Enterprise Applications. My expertise lies in leveraging the full potential of Microsoft, Amazon, Facebook technologies to deliver innovative solutions tailored to your business needs. 𝗪𝗛𝗬 𝗨𝗦 ✅ 6,000+ hours on Upwork and 30,000+ hours in total; ✅ 100% Project Success; ✅ Fluent English; ✅ We can help you to connect business needs with technologies; ✅ We have large experience building finance, health care, SAAS, etc. products; ✅ More over 15 years of development experience, driving scalable product architecture. ✅ Results-Oriented: I prioritize delivering solutions that align with your business goals. ✅ Efficient Collaboration: Excellent communication skills to ensure seamless teamwork. ✅ Attention to Detail: I adhere to the highest coding standards and focus on performance optimization. ✅ Timely Delivery: Committed to meeting deadlines without compromising quality. 🚀 𝗪𝗛𝗔𝗧 𝗪𝗘 𝗖𝗔𝗡 𝗗𝗢 𝗙𝗢𝗥 𝗬𝗢𝗨 - Web Development: Build dynamic and responsive web applications using .NET, NodeJs, Python, Java, Go and modern front-end frameworks like React, Angular, or Vue.js. - API & Microservices: Design and implement robust RESTful APIs, gRPC services, and scalable microservice architectures. - Database Solutions: Optimize your data handling with MS SQL, MySQL, Oracle, PostgreSQL, T-SQL, and NoSQL databases like MongoDB, Firebase or Redis. - Cloud Integration: Deploy and manage applications on Azure, AWS, or Google Cloud, including serverless computing and CI/CD pipelines. - Secure Solutions: Implement cutting-edge authentication protocols (OAuth, JWT) and adhere to secure coding practices to protect your applications. - Code Excellence: Follow SOLID principles, leverage MVC/MVVM patterns, and write maintainable, clean code. 🛠️𝗧𝗢𝗢𝗟𝗦 & 𝗧𝗘𝗖𝗛𝗡𝗢𝗟𝗢𝗚𝗜𝗘𝗦: - 🖥️ Backend: C#, .NET Core, .NET Framework, LINQ, ASP, ASP.NET, ASP.NET MVC, .NET API, ASP.NET Core, JavaScript, Node.js, Express.js, NestJS, AdonisJS; Python, Django, Flask, FastAPI, Java, Spring, Spring Boot, Hibernate, PHP, Laravel, Symfony, Go, Golang, Gin, Echo, Kotlin, Ktor. - 💻 Front-End: HTML, HTML5, CSS, CSS3, JavaScript, TypeScript, Blazor, React, React.js, Redux, MobX, Recoil, Zustand, Angular, Angular.js, Vue.js, Vuex, Material-UI (MUI), MaterialUI, Bootstrap, Foundation, Bulma, Tailwind CSS, PrimeNG/PrimeReact, Webpack, npm, Yarn, Gulp, grunt, SASS / SCSS, LESS, Babel, Progressive Web App (PWA), D3.js, Three.js, Chart.js. - 🛢️ Database Management: MS SQL Server, MySQL, Oracle Database, PostgreSQL, MongoDB, Redis, Cassandra, Firebase, Firebase Realtime Database, Amazon DynamoDB, Cosmos DB. - 🌐 Cloud & DevOps: Microsoft Azure, App Service, Azure Functions, Azure DevOps; AWS, Elastic Beanstalk, EC2, RDS, S3; Google Cloud, App Engine, Cloud Run, Firestore; Docker, Kubernetes, GitHub Actions, Terraform, Ansible, Apache, Nginx, Microsoft IIS, Caddy, Tomcat, Heroku, DigitalOcean. - Message Brokers & Real-Time Communication: RabbitMQ, Apache Kafka, Redis Pub/Sub, MQTT, WebSockets, - Monitoring & Logging: Elasticsearch, Logstash, Kibana (ELK Stack), Prometheus, Grafana, Splunk - Testing: NUnit, MSTest, xUnit, Moq - Version Control: Git, GitHub, GitLab, Bitbucket - Debugging & Performance Tools: dotTrace, ANTS Performance Profiler 🗂️ 𝗖𝗔𝗦𝗘 𝗦𝗧𝗨𝗗𝗜𝗘𝗦 𝗔𝗡𝗗 𝗣𝗢𝗥𝗧𝗙𝗢𝗟𝗜𝗢: For more details follow northsouthtech.co/blog/category/case-studies/ 🌟 Let’s Bring Your Vision to Life! Whether you need a custom web application, a cloud-integrated solution, or robust API services, I’m here to help. Let’s discuss your project and turn your ideas into reality! 💬 Ready to get started? Send me a message or book a call, and let's build something amazing together. 🔑𝗛𝗜𝗚𝗛𝗟𝗜𝗚𝗛𝗧𝗘𝗗 𝗦𝗞𝗜𝗟𝗟𝗦: Real Estate Software Solutions Marketing and Sales Software Travel and Hospitality Software Mining Technology Solutions Banking and Financial Services Software Healthcare and Wellness Tech Transportation and Logistics Software Entertainment Tech App Development iOS Android Web Development Services Custom Software Development Software Product Development Team Augmentation DevOps Services Quality Assurance AI/ML Software Development Blockchain Development Real Estate Property Listing Solutions Healthcare Software Development Marketing and Sales Software with AI CTO as a Service UI/UX Design Services Data Engineering Technology Consulting Dedicated Engineering Teams Product Discovery SaaS Design Platform Design Application Design Software Design Adaptive FinTech NFT Responsive Web Design SaaS Platform Prototyping Prototype Design Wireframing Clickable Prototype

  • C#
  • HTML
  • JavaScript
  • ASP.NET
  • TypeScript
  • SQL
  • .NET Framework
  • React
  • Redux
  • FinTech Consulting
  • .NET Core
  • Healthcare Software
  • Architectural Design
  • Cryptocurrency
  • Solidity
Hayk M.

Zlotoryja, Poland

$30/hr
5.0
4 jobs

I have huge experience in backend development. I have worked in this industry for more than 13 years as a CEO and Senior Software Developer and as a Full-stack developer. I have experience in: - Large scale projects - Highload projects - Multiple programming languages, including PHP, Java, Node.js, Javascript, Bash - Unit and Functional Testing - Search tools like Elasticsearch - Backend frameworks (Zend, Symfony, Laravel, Spring Boot 2, Express.js and other) - Modern Javascript Frameworks (Angular/Vue) - BDD, TDD - User experience - Managing a team of developers (Project manager/CEO) - Writing code following the standards(SOLID, DRY and other) - Database query optimization - AWS and cloud administration - Queues (RabbitMQ, ActiveMq and other) - API integrations - Database sharding and replication And more. I like to face big challenges. I am a team player.

  • MySQL
  • PHP
  • Symfony
  • Spring Boot
  • Java
  • PostgreSQL
  • PostgreSQL Programming
  • Material Design
  • API
  • Apache Kafka
  • RabbitMQ
  • MySQL Programming
  • Angular 10
  • Appian BPM Suite
  • Software Architecture & Design
Artem Z.

Wroclaw, Poland

$80/hr
5.0
3 jobs

I'm a senior technology leader with over a decade of experience building and scaling complex digital platforms (primarily in fintech, embedded payments, blockchain, and cloud-native architecture). As a Fractional CTO and Solution Architect, I help startups, scaleups, and enterprise teams define product strategy, architect robust systems, and lead technical delivery from MVP to full-scale platforms. I co-founded Idealogic, where I’ve led 70+ engineers and shipped 30+ high-impact products across regulated industries. I bring a hands-on approach to solving technical challenges while aligning closely with business and product goals. What I Do: - Architect fintech platforms (MoR, PSPs, KYB/KYC, payouts, compliance) - Design scalable SaaS systems and API infrastructures - Lead discovery, scope definition, and technical due diligence - Guide dev teams through delivery, CI/CD, DevOps, and QA - Translate business vision into actionable technical roadmaps Core Tech Domains: ✔️ Fintech / Payments ✔️ Blockchain / DeFi / Web3 ✔️ AI/ML & Data Pipelines ✔️ Scalable Cloud Architecture (AWS, GCP, Azure) ✔️ Product Discovery & Tech Strategy If you're looking for a technical partner, not just a contractor. I bring both execution and executive-level thinking to your project. Let’s talk.

  • Software Development
  • Architectural Design
  • Architecture
  • Blockchain, NFT & Cryptocurrency
  • Aviation
  • Real Estate
  • FinTech Consulting
  • FinTech
  • Node.js
  • React
  • Angular
  • Solidity
Vadzim A.

Szklarska Poreba, Poland

$35/hr
5.0
1 jobs

Highly skilled and results-oriented AI/ML Engineer with about two decades of experience in the IT industry. Experienced in developing and implementing modern Machine Learning models, Neural Networks, and Deep Learning architectures. Skilled in Computer Vision, Natural Language processing, and cloudbased solutions. Proven track record of implementing the latest technologies to optimize AWS bills and reduce production costs for numerous businesses. Adept at collaborating with cross-functional teams to deliver highimpact solutions. Passionate about staying updated with the latest advancements in AI/ML and continuously enhancing skillsets.

  • Artificial Intelligence
  • Neuroscience
  • Deep Neural Network
  • Data Science
  • Python
  • AWS CloudFormation
  • AWS Greengrass ML
  • Azure AI Vision
  • Azure DevOps Server
  • Java
  • PyTorch
  • TensorFlow
  • Keras
  • OpenCV
  • Machine Learning

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